Stefan Vyacheslavich Trifonov Sr.

"'With power and strategy, victory can be determined.' - Stefan"Prince Stefan Vyacheslavich Trifonov Sr. (Стефан Вячеславич Трифонов И) is a minor character of Mr. S and the main antagonist of Mr. T.

He was the second son, next to his younger brother Vasily, of Princess Alexandra Nikolayevna Gagarina of the Gagarin House in the Rurik Dynasty and Count Vyacheslav Vladimirovich Trifonov. Once a veteran KGB and VVS (Russian Air Force) Agent, the legendary World Champion of Duel Monsters (before his son, Seto, in his generation), and a Chess Grandmaster, he was the co-founder and CEO Emeritus of Trifonov Corporation, specializing in air defense, information technology, and aerospace development and research until his retirement and leadership was passed to his brother and co-founder Vasily Vyacheslavich Trifonov.

While he appeared as the estranged father of Sharon in Mr. S, it was revealed in Mr. T that Stefan was a widower who had two sons from his first marriage, Stefan II and Mitrofan. After Pierre's marriage to Sharon, Stefan became his father-in-law and a grandfather of his children.

In  Mr. S, Stefan firstly appeared as the estranged father of Sharon, who took her back from Myshkin Orphanage after eight years since he left her in the care of the Mother Superior in there. In  Mr. T, Stefan became a more complex character than he was in  Mr. S, up to the point of becoming the main antagonist until his redemption at the end.

Physical Attributes
A handsome man, Stefan appeared to inherit the Trifonov family's traditional good looks that include dark brown hair (which became white due to age), sharp blue eyes, and fair skin; however, it started to wane a bit due to age. Even though he passed middle age and the turmoil on his body due to stress is obvious, Stefan's physique aged slowly that he managed to look younger than any other man in his age. When Stefan was younger, he resembled his eldest son Seto strongly that even Oskar, Anton, and Dmitri noticed how Seto reminded them of Stefan in his younger years.

Stefan's everyday outfits mostly consisted knitwear, trench coats, scarves, and suits due to him to be a businessman and being accustomed to very cold weather like of his hometown in Russia, where the borders are close to the mountainous region of southern provinces in Siberia.

After his accident, he donned a pair of metallic prosthetic lower legs, and he had his customized walking stick to defend himself, extend as an extra arm, and help himself to walk. His white walking stick is also a stun cane and its hilt was carved after the white king chess piece. Without his prosthetic legs, he also used a wheelchair, but he rarely used it until his brief imprisonment in the Hague when he was not allowed to wear steel and bring his stun cane.

Personality
Even though Stefan was an upper-class man like the Trifonov family in its aristocratic years, Stefan was known to be a gentleman to others, regardless of class and country. Growing up in poverty during communist rule in Russia, Stefan grew up with responsibility in a young age, and he taught his children that by not inheriting them the wealth he managed to accumulate through Trifonov Corporation because he wanted his children to achieve greatness through the same kind of hard work that he had to go through. Stefan can appear to be polite and charismatic, which earned him mutual positive relationships with many companies and individuals; however, Stefan had a sharp tongue and its obnoxious, arrogant tone, one that was not without a sarcastic, insensitive sense of humor and his sophisticated means of display.

In spite of his gentlemanly manners and apparent sense of courtesy, Stefan had a high sense of pride in himself that was seen through his competitive nature and his tendency to save his face, which made him hard to gain others' respect sometimes, but Stefan meant well and he became respectful and humble to those who earned his respect, unless that person crossed the line. A prime example was Lena, his close friend and colleague since their Air Force days until their incident that made Stefan ruthless and unforgiving to her for many years later. Because of their close relationship, though, Stefan respected it to the point of bargaining with Lena to offer payment to her financial debts and medical care in exchange of her visiting rights to their daughter Sharon, who was considered to be his collateral.

A cunning man, Stefan was not above devising plans to set up those who were known with a negative reputation like the way he used his business ally Zigfried's plan to undermine Kaiba Corporation and his plan to tip off Skander's "thievery" in Trifionov Corporation to expose Skander as a cracker and charge Zigfried for industrial espionage and theft of Kaiba Corporation's trade secrets, even if Skander would suffer for more prison time and Schroeder Corporation would be destroyed.

Because of his status as management, he could be a holier-than-thou and judgmental person, especially toward people who he deemed to be inferior to him like the Smerdyakov (calling Pierre “servant boy”) and Kravenoff families (calling Ana “savage girl”) who were both redeemed at the end of Mr. S. Along with his fault-finding personality, he was very hypocritical toward others. He scolded Skander for disrespecting his children, while he was actually guilty for disrespecting Sharon by displaying how much he detested the girl. When he used to say wise sayings on how to be a family man, he failed to be a family man himself from his contemptible treatment of Vasily and his side of the family.

According to Vasily, deep within Stefan's calm and collected veneer was an embittered man who was envious of the people he looked down over the years, and this jealousy turned to contempt due to his prideful nature. No matter how hard he tried to have a normal life with his loved ones, it was actually difficult for him due to his life as a man who was extremely devoted to his career always colliding with his other life as a respectable head of his household and a father. When he saw Vasily and Dmitri very happy with their children, he was truly saddened by his inability to live a happy life with his own. In retaliation, he usually insulted them through their flaws as compensation for his own inferiority to them.

According to Pierre's private medical journal on Stefan's mental health, Stefan was mentally unstable due to his major depression and trauma from the unfortunate circumstances given to him. Stefan also had claustrophobia and hypersensitivity to loud sounds due to his direct witness of the explosion that killed his father. His wheelchair, which he rarely used since his accident, was also a trigger and a sign of weakness when it reminded of his separation from his two sons and struggle with his former executives. What was amazing was that there was no medical history of him taking antidepressants or undergoing therapy; however, it made Stefan emotionally crippled toward chronic aversion from those triggers instead of coping appropriately until he went out of control in the Hague. His forced separation from his sons and his realization of his firstborn son's corruption and cruelty made Stefan decide to leave the parental care of Sharon to Vasily and not to participate in his company's mentorship programs, even though he personally taught the Schroeders (and indirectly Skander) but only through computerized lessons, instead of personal contact.

Inside and outside of competition, Stefan was shown to be extremely fearsome and psychotically lethal, never known to show any mercy or affection or favoritism for his family in the tournament and saw them as enemies. In a young age, Stefan had ruthless tendencies like attempting to kill Vasily's pet dog Georgi because of its incessant barking. In the KGB and the Air Force, despite of him being older than many agents, Stefan was proven to be a ruthless hand-to-hand combatant who once broke a Wolf Spider's neck and broke a younger agent's skull (both of them were rumored to be dead), instilling fear in many of the Agents and sparking a rivalry and then friendship with Alexei Shostakov, the Red Guardian and fellow top pilot in the Air Force. Many years later, he was never shown to hesitate to trash-talk to his own brother at the beginning of the tournament, his own daughter after her loss at the quarterfinals, and his own son after his loss at the duel with him. He instantly changed himself from a reserved gentleman to a feared opponent, especially during his duels between Seto and Yugi, where he was ruthless and sometimes nastily sadistic to the point of psychotic, implying him to be more deranged and fearsome than others assume; however, he may appear like this on purpose so duelists, especially those who were like Bandit Keith, would not take advantage of his generosity. Nevertheless, he was a crowd pleaser when he made his opening speech with great applause, especially from his fans from Russia and all over Europe, and the crowd, even those who were new to him, was very enthusiastic about seeing him play against Seto and Yugi in the last two rounds.

In spite of Stefan's lethal ruthlessness and cunning that defined Stefan a cruel and severe man, the most redeeming trait of Stefan was his love of his family, especially his children, even though he favored Seto and Mokuba more than Sharon due to them being Tomoka's children, that lasted for a lifetime. In spite of the controversies spreading through Russia about his marriage, Stefan genuinely loved and cared Lady Tomoka, even after her dying day, that he fulfilled his word to take in Sharon (even though it was only in word when he put Sharon under care of Vasily) and in his episodes of depression, he dreamt of her when he lost both of his children to Kaiba Corporation. In spite of the frenemy relationship and his brief business rivalry with his brother, Stefan cared about Vasily as the only family that he had left since the deaths of his parents and his older brother Viktor. When Stefan finally saw that his family needed him more than the company, Stefan decided to keep his concession secret until the day of the takeover because he wanted Vasily to fight his way to the top without his interference like he had always believed.

Despite of his severity, Stefan had a couple of humorous habits. First was his sense of age fabrication. Stefan was always known to be extremely reluctant to disclose his age, and people who knew him personally like Lena, Dmitri, or Vasily tend to disclose it, much to his dismay. Due to the physical and attitudinal likeness with each other, Stefan and Seto became the butt of jokes from Vasily and Katsuya, who stated that it would be too cruel to say how old he was in front of Seto because that was what Seto would be in Stefan’s age. Second was his tendency to sleep during his idle times, especially during status meetings and lectures due to his lack of sleep and his growing age, which was a trait shared with Seto.

Skills
An accomplished gamer, Stefan was the Duel Monsters World Champion before his son Seto during his generation, and he was the Creator of the Blue Eyes Deck and Trap Cards, giving his subsequent names as the "High King of Dragons" and "White King". Even though he retired from the arena for more than 30 years, Stefan was still revered by older duelists like Arthur Hawkins and Sugoroku Muto and European duelists like Zigfried and Leon Schroeder (his former dueling protégés). Before that, he was a Grandmaster in chess with the Elo rating of 2750. One reason why Stefan's dueling strategies were almost flawless was his problem-solving skills that were strengthened by chess. Dmitri stated that Stefan's status as a duelist and a game maker was due to him lacking a happy childhood where he had to take a role as an adult at a very young age.

Even though Stefan resented his accelerated education program back at Russia, Stefan managed to excel at his subjects, implying high intelligence on his part. In the Main Intelligence Directorate, he was an accomplished high security hacker and dispatch pilot. Stefan was an above-average hand-to-hand combatant and strategist. In the Russian Airborne Troops, he was a celebrated Colonel of Aviation.

After his time at the military, he went to Moscow Aviation Institute from recommendations of the Russian Airborne Troops and managed to study abroad in Europe's elite business school because of his achievements in business and aerospace engineering. After his education, Stefan became a professional aerospace and avionic engineer for the Russian Space Forces and later for both TC and Kaiba Corporation when he personally established a catalogue of private space stations, satellites, and aircraft for both companies. Educated in the elite business school INSEAD, he became a competitive businessman who founded Trifonov Corporation, establishing himself as a true millennial in his time. He was also a computer engineer when he personally crafted Trifonov Corporation (and later Kaiba Corporation)’s catalogue of supercomputers. He was also experienced in biomedical engineering when he was the one who constructed and funded Vincent's in-vitro body.

Stefan was once a tenor singer in the Red Army Choir. Rumor has that he passed his singing ability to his children, especially Sharon who became a soprano in the Bolshoi Opera and Mokuba who became a tenor in the choir. Stefan was also an artist who personally drew the original art of the cards he created.

Aside from his native Russian (in a Northern Russian dialect like his younger brother), Stefan also can speak in multiple languages, including English, French, Italian, German, and Japanese.

Early Life in Russia
"'In my dreams, I dreamed of brighter times until I had to wake up with those visions gone.' - Stefan Trifonov"Before the Revolution, Stefan's paternal family were once a renowned noble line of metal craftspeople who were well-known for their crafted, priceless trinkets, and through his mother, he was blood-related to the House of Gagarin in the Rurik Dynasty, the former royal dynasty before the Romanov family, and his mother had inherited a fortune and fiefdoms within various locations in Russia, which was taken away by the Bolsheviks. In spite of the manhunt for nobles during the Russian Revolution, the remaining line of the Trifonov family is the only aristocratic family who did not emigrate to western countries. In spite of hiding from the Bolsheviks, young Viktor Trifonov volunteered to fight for Russia in WWII, but he died in action at the final days of Operation Barbarossa, one of the bloodiest battles in WWII history.

Childhood and Adolescence
Stefan was born in Orsk, the southern region from the Ural Mountains and the southern forest border of Siberia. Due to the economic crisis since WWII and the hyperinflation after the Russian Revolution, the wealth of his family declined dramatically into poverty, and Stefan took a lot of responsibility for his household, especially after his older brother Viktor died in action. Starting by the age of 5, Stefan worked with his father in the mines at the Ural Mountains until his father tragically died in the explosion when Stefan was 10 and being a witness of the explosion, he got traumatized from the accident that he later developed a high sensitivity of noise and claustrophobia. Because of his extensive absence from elementary education, Stefan found reading hard, so he was obligated by his aging mother to undergo a rigorous accelerated homeschooling program that he resented at first (and gradually enjoyed due to his growing curiosity in outer space); however, he excelled at his subjects, mostly in math and science.

Vasily was born when he was 12, and his mother died five years later, succumbing to her illness. Viktor's old war comrade Dmitri came to know Viktor's family situation, and he offered to take care of young Vasily without pay while Stefan pursued his compulsory education. Dmitri started to have concern on Stefan's ruthless tendencies in a young age, especially on Stefan's attempt to brutally beat Vasily's pet dog Georgi for its incessant barking. Stefan finished his studies in the gymnasium and worked as a civil servant for the government to support Vasily through the benefits given by the governor who favored him. Stefan offered Dmitri payment for taking care of Vasily once, but Dmitri utterly refused because Dmitri used his remaining savings and Stefan didn't need money to prove gratitude.

In the KGB and the Air Force
When Vasily was 18 and Stefan was 30, as advised by Dmitri, they went to the KGB Academy together to become Agents, where they were mentored by Dmitri, who was revealed to be an elite spy and senior KGB Agent. As Stefan's mentor, Dmitri feared about Stefan's ruthless tendencies in the KGB, especially from the incidents of fellow Agents. In spite of his older age among the other Agents, Stefan was feared to be ruthless and merciless during missions and training, in contrast to Vasily's more friendly, easy-going personality. Stefan was reported a few times, especially for breaking a Wolf Spider's neck, fracturing a younger Agent's skull, and even paralyzing a couple of agents that he had to train with Alexei Shostakov, who was an asset to the KGB and the government. After training, he, along with Vasily and a woman of his age named Lena, was placed in a sector of the elite Russian Air Force, where he served as a pilot and hacker. After noticing the pattern of dangerous missions given to the brothers and the sudden promotion given to him by the Director, Dmitri realized that the government was planning to terminate Stefan and his brother like how they succeeded with their older brother Viktor during WWII. Having the Director's good graces for his service for many years, Dmitri made a secret deal with him to surrender his promotion offer and his chance to have a better quality of life in exchange for the promotion and transferal of Stefan and Vasily to a more pacifist and academic department.

The Air Defense Force and the Creation of Trifonov Corporation
After his promotion as Colonel, he was referred to join the Russian Air Defense Force, where he had an interest in aerospace engineering and avionic production. Unaware of the true nature of his promotion, Stefan became overconfident to use the provisions of the department to establish state-of-the-art aerospace technology and build a corporation on his own. Wanting Stefan to gain the trust of the government, Dmitri disagreed and advised to distribute his efforts to the goals of the State. Dmitri also warned Stefan that Agents used their skills to fulfill the destiny of the State, not their own. Wanting a life that he claimed for himself, Stefan spat at Dmitri that he couldn't go far in life because he was a servant to every person's destiny that he could never master his own. Stefan's arrogance went too far to earn Dmitri's respect that Dmitri resigned from training them any further. Ever since that altercation, Stefan completely lost his respect to Dmitri, in spite of Dmitri's sacrifices for upbringing him and his brother.

In his spare time at the Academy and the military, he was one of the tenor singers in the Red Army Choir. While in the Air Force, Stefan attended the Moscow Aviation Institute with Lena and Vasily, where he attained his B.S in Avionics and Electrical Engineering and M.S in Spacecraft Engineering, and INSEAD in France, where he attained his MBA. His colleague Lena joked that Stefan graduated in honors by luck because he had a habit of sleeping when his mind was idle for a long period of time.

Investing in aircraft manufacturing and aerospace research, Stefan gained profits from unusual resources. An accomplished gamer himself, he gained a substantial amount of profit by winning the prize money from tournament to tournament. As the sole representative victor of Russia, Stefan became the legendary European champion and pioneering World Champion of Duel Monsters, gaining his reputation as the renowned High King of Dragons for his original ownership of the four-of-a-kind Blue Eyes White Dragon in the world. While he was a collaborator of Maximillion Pegasus to create the game of Duel Monsters, Stefan was the creator of Trap Cards and Counter Traps, and he was rewarded with Pegasus's friendship and a substantial amount of money. He also gained profit from his participation in international chess tournaments, where he gained his reputation as a renowned Chess Master. After gaining enough profit, Stefan, Vasily, and his aviator comrades established Trifonov Corporation, in which he became the President and co-founder Vasily as the Vice President. Stefan's workload for the company and the Aerospace Defense Forces during the Space Race forced him into retirement from the dueling ring. Even though he retired as a champion Duelist, Stefan remained to be a legend and his dueling techniques and strategies had always been flawless. While Trifonov Corporation had grown to the international scale, Stefan gave away his Blue Eyes White Dragon cards to his former war comrade and trading partner, Ambassador Leung Zhou from Hong Kong, his business partner and fellow duelist Drake Meinhardt from Germany, Professor Arthur Hawkins from America, and Joe Cord from America who had intentions of giving the rare card to his Iron Curtain comrade Dmitri Smerdyakov as his means of making amends.

As a Member of Russia's Social Elite
Stefan received many honors following his honorable discharge from the Russian Air Defense Force; however, his active participation in the Vietnam War and the Space Race prevented him to have business with America, which was a major downside of his service to his nation. In honor of his massive endeavors to the country and that of his maternal ancestors in Russian history, Stefan received back his fiefdoms and awarded various orders issued to his mother who was a direct descendant from the Rurik Dynasty.

In spite of his age, Stefan was one of the most-wanted bachelors due to his looks, wealth, and intelligence. Pravitel Ivan Konstantinovich Yaroslav once arranged his daughter Katerina's marriage upon multiple high-class suitors with Stefan being one of them. Stefan, however, refused to court Katerina because it was not in his highest interest: Stefan found her incorrigible to be a former Black Widow and a basket case to bear any children (Black Widow agents were sterilized before their training). Stefan let Katerina elope with Dmitri and kept their whereabouts a secret from everyone else, even from his own brother due to Vasily's close relationship with Dmitri.

As being part of Russia's social elite, Stefan knew White Russian socialites Sergei and his wife, Sasha Kravinoff, who was also born of royal blood. While he had some intrigue in Sergei for his longevity, he had disgust and contempt toward Sasha because of rumors of her as a gold-digger and her attempt to associate Stefan because of his money and royal status; thus, he had contempt for her and her children in the Kravinoff family. Stefan actually didn’t know that Dmitri and Sergei Kravinoff are actually related (they were half brothers).

Married Life in Japan
"'In Kaiba Corporation, Stefan engineered the technological foundations, including the supercomputers, aircraft, and satellites. Thanks to him, Kaiba Corporation was the first Japanese company to acquire a private satellite since the Space Race between the U.S and Russia.' - Roland"

Alliance with Kaiba Corporation
Not too long after the development of his company had flourished, Stefan met Gozaburo Kaiba, who represented Japan in the World Chess Championship. After facing Gozaburo in the final match and won, Stefan won his opponent's respect and received an opportunity to take TC globally from its contract with Kaiba Corporation. While the contract relocated him to Japan, Vasily took charge of the original branch of Trifonov Corporation in Russia. Even though Stefan was a foreigner, which were viewed unfavorably in Japan during his time, Stefan was decent and friendly with many Kaiba Corporation employees, especially his protégé Roland who actually wanted Stefan to be part of management in the company. After establishing a branch of Trifonov Corporation in Japan, Stefan became the main representative of Trifonov Corporation and KC's Vice President of Research and Development, placing himself in KC's Board of Directors. Even though TC was low on materials, Stefan and Kaiba Corporation managed to build satellites and supercomputers. Stefan's charisma and intelligence in science and business surpassed those of Gozaburo and the rest of the Board of Directors, implying distrust from Gozaburo and his loyalists.

Married with Children
During his temporary residence in Japan, Stefan, as a wealthy foreigner and socialite, met geisha Tomoka Saiku, who started his close relationship with her after a game of chess and a playful fight of wits. Later on, Stefan became Tomoka's danna until their marriage became officiated and Tomoka had to retire. Stefan and Tomoka got married and birthed their first son, Seto (Stefan II in his Russian birth certificate). When he came to know about Gozaburo as a danger to his family, especially Tomoka, Stefan kept his family's residence in Kyoto a secret, misleading Gozaburo and his associates with his spare address in Nagoya. Being a devoted husband and father while being head of his company, Stefan was close to his son and wife, but he had to go on business trips to Russia in acquiring more resources to build production for both TC and Kaiba Corporation. In spite of his commitment to work, Stefan acknowledged Seto's genius intellect when Seto managed to skip grades. Even though Stefan can truly see a prospective heir in Seto, Stefan wanted Seto to live with a happy childhood and know more about responsibility than power, so only Tomoka knew about Stefan's wealthy background and professional occupation and she didn't disclose anything about Trifonov Corporation to her son and anyone else.

One of his business trips resulted him being set up by his conservative executive Boris Razumikhin, who was secretly Gozaburo's mole with a share of Kaiba Corporation, to be forced into sexual assault by Lena, which resulted a bastard daughter, Sharon. Out of shame, he decided to leave Sharon in Myshkin Orphanage and go back to Japan to his family. His wife knew of Stefan's predicament and she announced that they were having another child, in spite of her medical condition after giving birth to Seto. Because Tomoka's condition gradually became terminal during the course of her second pregnancy, Stefan devoted most of his time to the welfare of his wife and son, in spite of the increasing pressure from Kaiba Corporation and liability from Trifonov Corporation. After giving birth to Mokuba (Mitrofan in his Russian birth certificate), Tomoka succumbed to her illness with her dying acceptance of Sharon as her daughter.

Being a single father wasn't a simple task. Even though Stefan was grieving for Tomoka's death, Stefan loved and took great care of his sons. Stefan taught his sons chess and every game that has ever been played, especially Duel Monsters. Stefan saw more of Seto's talent in computer engineering in a young age; however, due to Seto's intellectual and age differences among his classmates, Seto was ostracized and sometimes bullied, up to the point when Seto got involved into fights with the older kids, that he decided to let Seto finish his elementary education and place him in Razumikhin Academy. Stefan technically decided that Seto was not fit to be the heir of Trifonov Corporation due to his lack of social skills and his preference of technology over people. To cheer his sons up, he occasionally takes them to Tokyo Disneyland on their birthdays, and that's how Seto and Mokuba had dreams of opening a theme park one day. Vasily and his wife Adina visited them from Russia, and they loved their nephews so much that they temporarily stayed in Japan as Adina took care of her nephews and Vasily helped Stefan with the increasing pressure in TC. Due to the need of management in Russia, Vasily and Adina left Stefan to take care of TC's branch in Russia.

When Stefan was accused for attempting to take over Kaiba Corporation, he worked overtime to ensure the survival of his sons and Trifonov Corporation because of a lawsuit between Trifonov Corporation and Kaiba Corporation for not making enough materials for Kaiba Corporation's production of military provisions. He voided his sales contract with Kaiba Corporation and decided to run Trifonov Corporation on his own, which became an initiation of the civil war within Kaiba Corporation. When Seto was eight and Mokuba was three, Stefan got into an automobile accident, which turned out to be an assault on Stefan from Gozaburo's loyalists, that cost both of his legs and placed him in a coma. Stefan was wrongly declared dead, but because he intentionally never left any inheritance to his children, his in-law relatives couldn't seek financial support to afford taking care of more children, so they sent Seto and Mokuba to the orphanage in Osaka.

The Blood Contract
"'They're my life. They're my blood. And no parent should bury their children. I learned it the hardest way possible.' - Stefan Trifonov"

An Unprecedented Adoption
When Seto was ten years old, he challenged and won a game of chess against Gozaburo, who came to the orphanage for a publicity stunt, and Gozaburo adopted them due to fulfillment on his side of the deal with young Seto. Due to Stefan's life being kept into secrecy from his children, Seto had no knowledge of his father's work and his father's adversarial relationship with Gozaburo, and Gozaburo had no knowledge of his nemesis having children due to Stefan's privacy. When Stefan was discharged from the hospital, he looked for his sons for months, ending with the painful realization that his sons got adopted by the head of Kaiba Corporation and his past nemesis, Gozaburo Kaiba.

After Seto was close to completing his rigorous accelerated private-tutored education, Gozaburo realized about Stefan's living status and his adopted children's relation to Stefan after receiving a copy of the koseki of the Saiku household from a detective he hired and found a way of revenge against Stefan by involving Stefan's children. Gozaburo was about to euthanize Seto and Mokuba in the same way he terminated his ex-employees who were loyal to Stefan. Being disgusted with his cruel and inhumane treatment of his children and determined to save his children's lives, Stefan interfered and forced Gozaburo to give his sons a challenge of meritocracy to gain the legal right to inherit Kaiba Corporation and the family name, persuading that Gozaburo needed an heir to Kaiba Corporation after the death of his own child. Gozaburo agreed; however, he placed Stefan under a blood contract for while Gozaburo was allowed to give Seto and Mokuba the challenge for the Kaiba family name, Stefan was forced to leave his sons to Gozaburo. If Stefan would contact them in any way, they would be euthanized under Stefan's liability.

Even though Stefan was grieved to let his sons go and angered for his regrets and failures as a father, he believed in his sons' combined strength and willpower that can defeat a man like Gozaburo. While almost all of KaibaCorp's employees who were loyal to Stefan were terminated and assassinated by Gozaburo's loyalists, the only surviving loyalist of Stefan, his protégé Isono, became a spy for Trifonov Corporation and reported the welfare of Seto and Mokuba to Stefan without being detected by Gozaburo and the Big Five. Decided to move out of Japan and let go of the rest of his first family with a heavy heart, Stefan went back to Russia.

Deal with Lena
Understanding the meaning of the fate of his sons as a punishment for abandoning Sharon in the orphanage, he decided to take Sharon from Myshkin Orphanage as his reluctant means of penance, in spite of not feeling any love for his daughter. When Stefan took Sharon away from the orphanage, Stefan met a 10-year-old Pierre. Stefan was both intimidated and impressed by Pierre's maturity, which reminded him of Seto. According to Vasily, Stefan owed a lot to Pierre for being a guardian figure to Sharon that he failed to be, which made Stefan have a mix of admiration and fear of the young boy. When Lena discovered her daughter Sharon, who ran away from Stefan's home, Stefan, with the least amount of mercy and respect to their close relationship, made a deal with Lena that he will pay for her financial debts and medical treatment for her mother, while Lena will surrender her visiting rights from seeing Sharon, who Stefan crudely considered to be her collateral. Conflicted between taking care of another child after losing two of them and taking care of Trifonov Corporation, Stefan eventually cut his losses and became extremely focused on recovering Trifonov Corporation from its tragic economic crisis, leaving Sharon under the primary guardianship of her aunt and uncle.

Descent to Depression
The tragic losses of Seto and Mokuba and its horrific nature became the darkest hour for Stefan and his entire family. According to Vasily, Stefan was under severe depression that he had sleepless nights for months and he was reduced to eating one meal a day. While Vasily and Adina regretted that he didn't take Seto and Mokuba into their care after Trifonov Corporation closed the contract with Kaiba Corporation, Stefan regretted that he didn't choose to take Seto and Mokuba to Russia and continue to raise them with Sharon. After taking Sharon in from the orphanage, Stefan, still unable to cope with the separation from his sons, left the care of Sharon to Vasily and Adina, who gave her the best education and opportunities, including her intensive training in the Bolshoi Opera and her tertiary education in Harvard University. Even though Stefan wasn't always present while taking care of Sharon, Stefan was very impressed with Sharon because she knew how to be financially independent with a bright future as a lawyer. For a while, Stefan became a sponsor to Schroeder Corporation and became a teacher to both Zigfried von Schroeder, his brother Leon, and indirectly Leon's personal valet, Skander, teaching them computer programming. Seeing Seto and Mokuba coincidentally after winning the World Chess Championship and watching Seto win the World Junior Chess Championship from a safe distance, Stefan learned from Isono, who was their chaperone, that Gozaburo committed suicide.

Conflict with the International Criminal Court
To his happiness, Stefan learned that Seto and Mokuba gained the legal rights to inherit Kaiba Corporation and managed to usurp Gozaburo from his power, freeing themselves from Gozaburo's tyranny. He came to know about Seto's World Champion title. However, Stefan also learned that Drake Meinhardt of Germany and Ambassador Long Zhou of Hong Kong had been forced to bankruptcy and suicide respectively, and Joe was wrongly convicted of larceny with three of the four copies of the rare card had been taken. Stefan was concerned about the owner of the last copy of the rare card that he visited Professor Hawkins, learning that Hawkins gave the card to his Japanese friend, Sugoroku Muto, and the card was safe. Learning from Isono that Seto bought Zhou Tradings and attempted to destroy Meinhardt Industries, Stefan correctly deduced that Seto was the one who took Zhou's life, assaulted Meinhardt's business, and framed Cord for stealing the rare card.

The Zhou family, who took refuge in Singapore, reported the wrongful death of Zhou and many others who died protecting Zhou to the International Criminal Court, and they also demanded remedy from Stefan because he was the main benefactor of the rare card that put Long Zhou and his family in danger. Under the ruling of the Hague Service Convention and orders from the International Criminal Court, Stefan proposed that in exchange for the clearance of charges, Stefan had to confiscate the rare cards in the custody of Maximillion Pegasus and turn in the true perpetrator for the death of Ambassador Long Zhou to the International Criminal Court as a remedy of the Zhou family and Hong Kong. Even though he hated the idea of turning his own son to the International Criminal Court, Stefan had great concern for his son's greed for power and his potential of becoming a weapon for destruction; however, because the Board of Directors can use Stefan as a possible way to take over Kaiba Corporation and Isono shut down his means of communication to prevent them from knowing Stefan's connection with Isono, Stefan had no other choice but to wait for the best opportune time to return to Japan. Losing his sense of belonging in his home country and his interest to be part of his country's affairs, Stefan stayed in France for a short while and then in his personal space station, where he directed his business remotely.

After all members of the Board of Directors was confirmed to be dead, Stefan managed to contact his old dueling friend Maximillion Pegasus to lure Seto into dueling him and obtain the rare cards, but Pegasus failed and Stefan waited for the day to duel Seto himself. After knowing that his old friend Pegasus failed to retrieve the other copies from Seto, Stefan requested him to remake the last copy of the card. Pegasus decided to remake the card under the conditions that Stefan had to put this under secrecy for that he would be in hot pursuit. Stefan reassured him that he'll only play it in a duel against a worthy opponent.

Creation of a Future Loyalist
After Sharon's departure to Boston, he was planning to hack into the supercomputers of Kaiba Corporation to gain contact to Seto and Mokuba; however, Stefan encountered a back-up file with the digitized mind of Noah Kaiba in the supercomputer. Finding a person worth saving in the poor boy, Stefan built a human body out of a stem cell and a surrogate egg from his sister-in-law Adina through the in vitro fertilization method and developed Noah's body in TC's research labs and private space station. Before Stefan successfully connected Noah's consciousness to his physically matured body, Stefan altered Noah's memories that he couldn't remember his past life, believing that Noah would be better off without knowing his biological father and living with a name of shame like his sons did. When Noah woke up in his new body, he only remembered his name but not who he was back then except with little memory. Stefan sent him to Vasily and Adina to adopt. When the brain of Noah's new body started to develop, Noah's consciousness started to conflict with the consciousness from the new body, creating another personality of Noah named "Vincent". Following his adoption and his informal name change, Vincent was trained to become the next Vice President of Trifonov Corporation, which included Vincent's accelerated education program and his undergraduate education at TIARA. Keeping observations on Vincent, Stefan also remembered Vincent’s past life as a Kaiba so he noted the auditory and visual cues that may ignite his memory and his Noah personality.

Throughout the course with Sharon and his newly adopted nephew, Stefan did not say anything about his past with Seto and Mokuba to Sharon and Vincent. The people who knew everything about Stefan were his brother Vasily and his two remaining trusted agents Isono and Fugita.

Conflict of Interest
In many months before the events in Mr. T, Stefan passed the presidency of Trifonov Corporation to Vasily and became the Chairman. Stefan became less content in his current position due to his inability to let the company go. Along with some other members of the Board, Stefan disagreed on Vasily's will to let his protege Katsuya Jounouchi to be his future successor next to Vincent. Due to intense disagreement with his brother, Stefan acquired the company back from Vasily and took over as its CEO emeritus, demoting Vasily and Katsuya from the C-Suite to the Executives and letting Vincent to remain on his side due to the fact that he was the creator of Vincent's artificial body. Vasily was initially reluctant to fight until he knew that the future of his company would be in jeopardy when Stefan would let his loyalists abuse their power and threaten their workers. At the beginning, Vasily and Katsuya managed to gain shareholders, but Stefan was still too strong. Vasily decided to expose Stefan's secret relation to Seto, who was a powerful figure of fear by the shareholders because Seto's reputation as a ruthless, cutthroat investor and their company's negative history with Kaiba Corporation, and claimed that Stefan would use his son to gain Kaiba Corporation as a battery for himself and his supporters. Thus, Vasily gained more shares for the company and attention from the press, which he took advantage later on.

Schroeder Corporation and Skander
In turn of the events, Stefan had to improvise. By pure coincidence, he received a message from his beneficiary Schroeder Corporation about the change of staff, which included Vladimir Kravinoff as the new CBO and Skander Zarubin as its cybersecurity specialist. Knowing Schroeder Corporation's damage to Kaiba Corporation due to its long rivalry with Kaiba Corporation and Skander's reputation as a professional hacker and thief and noticing Vladimir's resemblance to Seto and relation to Sasha Kravinoff, Stefan played with Zigfried's intentions to undermine KaibaCorp by communicating with his KC informant Isono to allow a spy to hide in Kaiba Corporation as a decoy and another spy to hide in his home. He plotted this to put Schroeder Corporation into disgrace.

When Boris and Stefan found out that Skander was an orphan looking for a family, they cruelly took advantage of Skander's need of a family and crudely used Skander to pose as Stefan's "Heir" to prevent Vasily from taking any more power in the company and the press. After reading about his past from records, who recognized Skander as one of the orphans, Stefan pretended to welcome Skander in his home and lied that he left Skander to his aunt because he wanted to keep his identity secret, just as he had done with Sharon. Stefan set Skander up to expose him as a thief by giving Skander delivery errands to the Yumeta Bank and bribing a bank official to forge records of “transactions” of withdrawals from the company to a transit Sberbank military account belonging to the Zarubin family, Skander's biological family.

Reunited with Kaiba Corporation
During the annual business gala with the new Kaiba Corporation, Stefan saw his firstborn son Seto as the CEO of Kaiba Corporation for the first time in twenty years, and in there, he was informed of KaibaCorp's 10th Anniversary of its opening day of Kaiba Land and its celebratory tournament, the KC Championship of Legends. Seto met Stefan without knowing that Stefan was his biological father, and Stefan entertained and impressed Seto and other investors through an intense game of chess, which turned out to be a draw. As he withdrew temporarily in a private office, he met his daughter's childhood friend and fiance Pierre Smerdyakov. Stefan went his way with his insults toward Pierre, Sharon, and Dmitri; however, Pierre remained steadfast and unscathed with the insults until Stefan threatened that if Pierre would continue his investigations about his secrets that were kept in Kaiba Corporation, trouble would come to the "Heir". Stefan met his loyal KC informant Isono. After conferring about plans to take down Schroeder Corporation, Isono disclosed something sensitive about Mokuba that left Stefan in complete concern.

Stefan observed Mokuba in the business gala as well, considering him as the dark horse. Despite of his inability to play the strategy games that his brother was typically good at, Mokuba showed himself as a good sport and learned every game just as he was able to learn from the players. Knowing that Kaiba's weak spot was in socialization, Mokuba also became a conversationalist, which impressed both Stefan and Vasily Trifonov of Trifonov Corporation, much to Seto’s dismay. In the main event, Mokuba managed to win in the interest of many more investors than Seto, namely the Trifonov family from Trifonov Corporation and Mads Meinhardt from Meinhardt Industries, with his sweet wit, empathetic personality, and business-savvy cleverness by dancing beautifully with the maiko and geiko performers, which reminded Stefan and Vasily of the late Lady Tomoka, and showing some of his visionary plans for Kaiba Corporation that he generated for four years.

He also answered other questions from investors, especially about his "homosexuality". Mokuba truthfully replied that he was not gay, and just because he was about to be converted to the Church, it didn't mean that he and the Church were discriminating against homosexuals at any kind. Mokuba answered that what people should understand about this is that homosexuality is against the teachings that he chose to believe in, and he chose to believe in these teachings because he always had faith in God's promises, even if he had to suffer for them. In society's terms, like religion, sexual orientation is a choice made by the free will of the individual, and whatever choices anyone would make, Mokuba would have to respect and protect them because he knew what was like to be persecuted because of a choice he made.

Mokuba's insightful answers impressed the crowd and shocked his own brother by telling him that he would rather lose his profit over his principles and saying with a nasty smile, “No one loves a sore loser, nii-sama, but everyone loves a winner and you’re looking at him.” Getting it on camera, Pavel snickered at his victory and karma served on Kaiba, while Max just said, “Payback’s a b$&@.” After Seto stood up from his table and faced Mokuba in a stand-off, Seto abruptly quietly threatened, “I’ll destroy you,” and left the room after a humiliating defeat to Mokuba’s cunning and cleverness that Seto had underestimated. He won positive attention from the majority that many investors were interested in investing in Kaiba Corporation as soon Mokuba takes over.

This moment was how Mokuba won approval from both Stefan and Vasily and became a middle ground in the power struggle between them, much to Boris’ dismay. When Seto angrily demanded Mokuba to go home before he could embarrass himself even more, Mokuba scathingly replied that Seto was the real fool. When Stefan saw Seto and Mokuba, he saw with disgust on how terrible Seto was to Mokuba out of envy and competition after hearing that Mokuba was actually HIV positive and was prevented from any business interference with the major shareholders and the investors because of his different beliefs, realizing how he was needed more in his family than in his company and the apple didn't fall far from the tree when it came to Seto's attitude and how it mirrored Stefan’s recent treatment of his own brother.

Competition Analysis
Preferring Mokuba to lead Kaiba Corporation over Seto and knowing that the only way to turn the investors' interest over to Mokuba was to defeat Seto in a duel since Seto didn't defeat Stefan before being the World Champion in the past, Stefan decided to register himself with Vasily, Sharon, and Vincent to represent Russia. Seeing how the company would had been better under Vasily's control than his own and how his family would had been better with his presence, Stefan knew that his retirement would come once his secrets would be out in the public and he would have to break Sharon's remaining loyalty to him so Sharon would surrender her shares of the company to her uncle. Wanting his brother to keep on fighting and come out of his shadow, however, Stefan kept his concession a secret, especially from Boris who adamantly wanted Stefan to remain in power due to his personal financial crisis since his academy had shut down and increasing fear of Vasily's administration to replace him with his wiser older brother Oskar in his current job.

Spying on Schroeder's Servant
Stefan noticed Skander with Mads Meinhardt, who immediately recognized and convinced him to return to Germany with them. Skander refused the offer, claiming Stefan and the others that he had never known them. As Stefan escorted Skander, he had a hunch that Mads would call Vasily because Vasily and Mads were close friends in their personal and business lives, so he secretly created a copy of Vasily's SIM card and hacked into Vasily's mobile phone. As intuited, Mads called Vasily that night about the real meaning of Skander being shown in the press as Stefan's "Heir". Mads told the entire truth of Skander's past as an orphan and former thief who actually saved his family from bankruptcy after Seto threatened his father for his authentic copy of the Blue-Eyes White Dragon, and he pleaded to Vasily to protect Skander and not to submit him to the police because the boy suffered 10 years in prison by the age of 14 because of his involvement in Seto's theft. Under Vasily's nose, Stefan overheard the entire conversation, remarking that just because Vasily would keep his word, it didn't mean that he would not.

As Stefan decided to withdraw his sponsorship to Schroeder Corporation to prevent Zigfried and his spies from harming the future of Kaiba Corporation, he contacted Isono to contact the decoy spy to access to high-security places because he expected Skander to hack the computer system due to being used by both him and his brother Vasily and having to sustain his damages. As expected by Stefan, Skander used the company's computers to hack into Kaiba Corporation's computer system and manage to steal trade secrets for Schroeder Corporation in the next morning. Knowing that his real sons will be at the tournament and Skander may hurt them, Stefan didn't invite Skander on the family entourage to Kaiba Land, under the false claim that he needed Skander to watch over the company premises. Unknowingly to Stefan, Skander stowed away in Vasily's jet to join them.

Scars and Struggles
In the tournament registration social, Seto was cordial with him until he learned Stefan's previous ownership and creation of the Blue Eyes White Dragon cards through Pegasus. Seto and Stefan argued about the cards, and Stefan bluntly roasted him that those cards failed Seto to be crowned as the King of Games and out of all his successors who owned the card, Seto was the greatest disappointment for someone worthy to own the cards and even his own company. Provoked by Stefan’s nastiness that matched his own, Seto lost words with his feelings unexpectedly hurt, and Stefan saw that expression as his cue to leave and curtly thanked him for the party.

Unfortunately, this rocky encounter between Seto and Stefan eventually resulted Seto's threat to Mokuba regarding his hostile takeover and Boris' torture of Mokuba afterwards. When Seto paid him with a substantial sum to have Mokuba "not beaten but broken", Boris brutally tortured Mokuba, not because Mokuba was rumored to be gay but because of Mokuba's resemblance of the late Lady Tomoka, who he deeply despised due to her more humble background, and knowledge about Boris' crude use of Skander, who he knew to be an orphan, to maintain power through Stefan. Seeing Mokuba crying out for help from his brother, who cruelly witnessed it without a thought of stopping the torture, Boris' son Rodion, who witnessed the traumatic torture in silent tears and knew Stefan's relation to Seto and Mokuba early on, was reminded about the brutal torture of his gay cousin Kolya until his death and secretly left the room to inform Stefan about his father's actions and motives. When a devastated Stefan and Rodion went to the room where Rodion reported that Mokuba was tortured, Stefan saw his unconscious son who just got beaten on the table. Rodion informed that Seto bribed Boris to torture him, and Stefan realized that Boris' loyalty depended on who paid him more and was devastated that Seto was not above to bribe someone like Boris to torture his own brother out of competition for the control of the company.

Oskar, who saw through Stefan's charade the entire time, came to Stefan's aid to escort the injured Mokuba, who was close to dying from his wounds. After Stefan took a beaten Mokuba to the KC hospital, Oskar testified that Boris had been persecuting and torturing homosexuals, even those in his family like Rodion and his cousin Kolya who got killed in his orders, and he was also responsible for the xenophobic libel and slander against the late Lady Tomoka due to her race and misogynistic treatment against Lena who he used to demerit Stefan's image as a faithful, devoted husband and open an opportunity for Gozaburo, who bribed him out of his sexual obsession for Lady Tomoka, to pursue Lady Tomoka. When Lady Tomoka passed away, Gozaburo displaced his obsession on Mokuba, who he routinely raped in the similar torturous manner that Boris had done. Finally snapped, Stefan was extremely angry at himself for his ignorance and arrogance that blinded him from the sufferings of his own family that were in the hands of someone he trusted; thus, he became more determined to defeat Seto in the Championship and put his plan forward to punish Boris for his treachery.

Later that night, Rodion was murdered by his own father when he came back to Trifonov Corporation headquarters to confront him for his questionable actions. In the next morning, Mokuba's body disappeared from his hospital room, implying that Mokuba apparently died out of severe blood loss.

In the KC Championship of Legends
Throughout the Championship, Stefan was proven to be a lethal, fearsome competitor, as predicted by Mokuba. While grieving for Mokuba's apparent gruesome death, Stefan nevertheless kept a competitive facade and fought a long way through the tournament, defeating Drake Meinhardt, his veteran rival representing Germany for Western Europe, in the preliminaries and Rafael, the prodigious Guardian Duelist representing America, in the quarterfinals and placing himself into the semifinals with Seto, who brutally defeated Sharon in the quarterfinals. After Sharon’s defeat and humiliation in the hands of Seto, Stefan secretly apologized to Tomoka for not fulfilling in his promise and Lena for not believing in her loyalty and innocence, and he apparently disowned Sharon as a bastard child and a great disappointment, shocking Vasily, Adina, and Vincent with his behavior. To make matters worse for Sharon, Sharon and Pierre had a spat that eventually broke their engagement. Vasily withdrew from the shock shortly after Stefan left the scene to gain opportunity to get Sharon's shares of the company, telling Sharon that Stefan was no longer worth the loyalty she gave him and she should go to her biological mother, who was still alive and looking for her, even if it meant to leave the Trifonov family for good.

Before their Semifinals duel, Stefan decided to raise the stakes on their coming duel by lying that once he sealed his ownership of Trifonov Corporation from any chance to put it into his brother's hands, he would make a deal with Pegasus to change the three-of-a-kind rule (which was a rule created by his brother and fellow cardmaker Vasily) into a full-house rule that would allow one of them to use all four of the Blue-Eyes White Dragon cards. Knowing Seto's competitive greed and weakness to power, Stefan tempted Seto to wager all of his three Blue-Eyes White Dragon cards and the Blue-Eyes Ultimate Dragon, while he wagered his remade fourth copy of the Blue-Eyes White Dragon, his White King card, and his powerful Aragorn card that could make Seto the most powerful duelist in the world that the investors would always keep in faith to invest more in his leadership of Kaiba Corporation. Overconfident due to the fact that Mokuba could no longer be in his way, Seto naively fell into Stefan's temptation and agreed to the terms, believing that he would never lose to an older duelist and these powerful cards could help him defeat Yugi in the Finals and become the new King of Games.

Determined to make some sense to him, Stefan studied Seto's strategies ahead of time and countered his traps one by one. While Seto got more than he bargained and found Stefan as his most challenging opponent but strangely familiar, Stefan revealed Seto as being too predictable for not only he was the one who created every card that he owned but he taught Seto the game in the first place because while he was his father. Almost to the end of the duel, Stefan chastised Seto for his greed and his willingness to put lives on the line for his selfish ambitions, something that he couldn’t allow for his first-born, and he declared that Mokuba was his true son because he was able to rise to the top without cruelty and win over Seto with his kindness. While Seto was overwhelmed by the truth and angered by the mention of Mokuba's name, Stefan saw through Seto's emotions and won the duel through a combination of Galadriel's special ability that destroyed the three Blue-Eyes White Dragons on Seto's side of the field and a Fusion Summon of the White King [Aragorn (with the use of Anduril the Flame of the West) and a reborn Blue-Eyes White Dragon] to obliterate the rest of Seto's life points. Shattering Seto's pride and crippling his confidence, Stefan took the three Blue-Eyes White Dragon cards, the Blue-Eyes Ultimate Dragon, and the Blue-Eyes Shining Dragon from Seto, handicapping Seto's deck and forcing Seto to retire early from the game.

After knowing Yugi defeated Katsuya in the Semifinals, Stefan decided to play with a combination of his original deck that he used as the High King of Dragons and his current deck to test Yugi Muto in the final round whether he was worthy to succeed him as the King of Games. Even though he managed to summon all of the three Blue Eyes White Dragons in one turn, negate Trap Cards with Dragon Spirit of White and Blue Eyes Shining Dragon, and use combinations of strategies with Galadriel and King Aragorn, Yugi, realizing the flaw in Stefan's strategy, managed to win on the brink of 50 life points remaining with his Dark Paladin, the Fusion Monster of Dark Magician and Buster Blader, which Stefan remembered and recognized to be his brother's other creations besides the Red-Eyes Black Dragon, strengthened by the numerous Dragon-Type monsters in Stefan's Graveyard, and destroyed Stefan's Blue Eyes Shining Dragon and Stefan's life points. After the thought of Vasily's vengeance from Yugi's cards was fulfilled, Stefan ultimately accepted Yugi Muto as the true King of Games and retired from the dueling arena.

Adding Insult to Injury
After the duel, Stefan received a message from Isono that somebody was in Kaiba Land without invitation and claimed to be in his party. Stefan, Vasily, Adina, and Noah rushed to the scene, only to find nothing in the scene except the gun. Even though the gun was marked with a combination of Skander and Seto’s fingerprints, Stefan called the police to dispose Skander and instructed Isono to call the police on Vladimir for trespassing and corporate espionage.

Knowing that Pierre was wounded, Stefan went in the KC Hospital and encountered his former friend, Anton Chekov II, who came from New York. After reminiscing the moments in his shared past with Anton and knowledge about Anton's unrequited feelings for his distant cousin, Katerina Yaroslava, who was also Stefan's former fiancee and Pierre's mother, Stefan cruelly blamed Pierre for his own injury, Stefan snidely smirked that Anton had done a good job raising a noble knight for his princess, especially because Pierre would soon be with his dead mother in heaven. A fumed Pavel was angry to Stefan for insulting his father and two of his close friends that he had to be held back by his father and Ivan. Anton calmly countered, "Well, at least her son would die doing the next right thing, as opposed to your own son, Stefan."

After saving Pierre's life, Skander turned himself in. Due to Pierre's fast communication with one of his lawyer connections in Japan, he was granted a trial and got cleared. Stefan became devastated with his own son Seto's mental breakdown in the court. He became cross with Isono's last-minute betrayal and sparing Vladimir's life. Stefan was very discontent with the outcome and became cross with Pierre for freeing a thief. In turn, Pierre told that it would be against his principles to not save Skander because he saved his life and Skander was innocent for the first time in his life. Dmitri countered Stefan’s accusation by telling him that Seto was far more worse than Skander and scolding him back for betraying his own flesh and blood because of his own shame. When Stefan insulted the late Katerina in front of Pierre, Dmitri got into a physical altercation that he almost strangled Stefan and Stefan stunned Dmitri with his stun cane. When Stefan was about to give Dmitri the final blow, Vasily knocked Stefan out with his air pistol. The Smerdyakov family left for New York.

Withdrawal of Power and Pride
Seto's identity as Stefan's firstborn son with overwhelming proof, including photos, the koseki and the enrollment records, was publicized a few weeks later after Skander's trial and shots of Stefan's recent actions, including his disownment of Sharon and disposal of Skander in the trial, portrayed Stefan as a person of controversy; thus, it rendered Stefan virtually powerless in the sight of the shareholders in his own company.

Thanks to Sharon's surrender of shares, Vasily gathered enough shares to take over the company and won the trust of the major shareholders. With support from outside companies like Meinhardt Industries and a surprise statement of concession, a petition of no confidence, and Vasily's approved programs with his signature before the Championship from Stefan, Vasily officially took over the company, resulting the immediate termination of Boris in the favor for the promotion of Oskar as Chief Diversity Officer and the new Headmaster of TIARA, angering Boris.

In defense of both Stefan and Vasily, Vincent rhetorically questioned where did Boris' loyalties lie and why would Boris deny his treachery, stating his recall of Gozaburo bribing Boris with a 0.5% share of Kaiba Corporation in exchange of Stefan's late wife years ago by framing Lena, who he knew to be Sharon's biological mother. Boris glared at Vincent and asked him how did he know about that and who Lena was. Vincent held his hands and replied in Russian and Japanese, "You were not the only father in that room because he was mine."

An angered Boris saw that his hands were handcuffed, and "Roman", the INTERPOL agent who was revealed to have a striking resemblance to Rodion, arrived to arrest him for corruption, murder, and embezzlement. Everyone in the room, except Vincent, was shocked to see "Rodion" alive, especially Boris. "Roman" sarcastically remarked that Boris was just shocked that he expected one of them dead or forgotten. Boris retorted that he could never forget Rodion and Roman, especially a hero like him. "Roman" whispered in response, "Funny you said that because you killed the real hero: Your favorite son." Remembering that he found out that the "Rodion" who was with him for many years was actually Roman through the secret correspondence between him and Vincent, Boris was in complete shock and horror when he thought that he apparently killed the real Rodion who he mistook for Roman, instead of Roman who he wished to kill for honor. When Boris begged Oskar to spare him, Oskar told him that he brought dishonor in their family name by putting blood on his hands, first his son and ex-wife and then his own.

Boris spat at Stefan for his concession to the proxy war to Vasily and that he was just an abomination like that thief (referring to Skander) and his "gay" son who resembled that Japanese "prostitute". As INTERPOL officers arrested Boris for corruption charges, Boris retorted that there was no evidence of corruption, and in return, Rodion showed the evidence from a CD and steered clear as Lena came inside. Lena smirked at Boris as she said, “It’s payback.” When Boris attempted to strangle her, Lena pushed him strongly to the wall and cornered him as she implied that Boris was the one responsible for Lady Tomoka's emotional distress in her first two years in Russia and this moment was not only justice for her and her daughter and Oskar and his son but also for Lady Tomoka and her son.

With the least amount of mercy she had left for Boris, Lena requested Boris to apologize and kneel for forgiveness to Mokuba, who was shown to be alive and well. Mokuba was revealed to be saved by Lena and Dmitri, who transported to another hospital where Dmitri donated his blood to save his life and Lena revealed Mokuba about his true parentage and everything in between. After struggling to get up, Mokuba told Boris that Seto can no longer pay him and requested the sum that Seto paid him and the 0.5% share of Kaiba Corporation that Gozaburo lend him because no person in his right mind would pay in exchange for his own death. Mokuba forced Boris to kneel down and confess his sins against him and his late mother. Navigating himself through his grief of his son and his collapsing pride, Boris apologized that he almost tortured him to death and his mother had to suffer. Finding solace and justice for him and his mother, Mokuba only forgave Boris because he had no right to condemn Boris. After Boris was taken away by INTERPOL, Mokuba finally encountered Stefan as his father and asked him why did he had to hide so much from his own family and did he knew how long his sons had to suffer without him, and Stefan tearfully embraced him and told Mokuba that he missed his sons so much and apologized for delaying the truth and letting them to suffer for so long, especially Mokuba. Stefan told Mokuba that he was proud of the man that he had grown into and his mother would be proud as well.

Roman revealed that his opposition activist mother had him to switch places with the real Rodion following his parents’ divorce because of their political agenda as members of opposing parties and their willingness to have them to participate in their political ambitions. Rodion was once conservative and ambitious in politics like Boris, so their mother decided to take Rodion under her custody and leave Roman under Boris’ custody without Boris knowing. While Roman posed as "Rodion" and he was educated in his father’s terms, the turning point was the time when he accidentally witnessed his cousin Kolya with his then-boyfriend Viktor and reported the incident to his father, which indirectly resulted Kolya being among the people who were kidnapped and tortured until he died in the anti-gay purges. The news about the purges were spread out quickly that Rodion, who posed as "Roman", knew about it, and Rodion knew how close they were to Kolya that he decided to withdraw from politics in exchange of investigative science. Rodion become part of the INTERPOL as “Agent R”, intending to give justice. As an agent, the real Rodion, with the help of Lena, had been tailing his father for his charges of corruption that stopped in Japan when he decided to confront his father for his charges and switched places with Roman. The real Rodion took his identity back and died when Boris mistook him for Roman and murdered him; Rodion saved Roman's life. Owing a life debt to Rodion, Roman returned to being "Roman" and became an INTERPOL agent in his brother’s place to arrest Boris and give justice to both Kolya and Rodion. Roman apologized to Oskar for Kolya's death that he felt partially responsible for; Oskar embraced him that he already recognized Roman since day one and told him that he was proud of Roman for what he did, something that Boris could never do for Roman.

Vincent told Roman that he also already knew that he was Roman, just as Roman was the only man who knew that he was Noah and they referred each other by their real names. Stefan realized that Vincent finally attained autonomy and control of his personalities without any mental breakdown, and he realized that it was because of Vincent’s quarterfinal duel with Yugi that brought back memories of his past life and the transition was smoother because of the relationship between Noah and Roman that made Vincent tolerate his "Noah" personality and let it flow with his current personality as Vincent.

Boris was repatriated back to Russia for his multiple charges, and then he was killed in prison a few weeks later.

Seto's Downfall
After the drama from his unexpected concession, Stefan closed his lifelong chapter with Trifonov Corporation permanently, even refusing to remain in the company as an Advisor and respecting Vasily's decisions for the greater good of the company. After fulfilling his word to the ICC and forwarding his secret addendum with them, Stefan was about to see Seto in the psychiatric hospital in Tokyo until he saw and overheard Shizuka's entire visit and conversation with Seto since Seto's fiasco in the court. Shizuka showed the revived version of the former koseki of the Saiku household that she retrieved from Yoshi-san with the Trifonov family seal that recorded Seto's adoption and return to the family. Then, she presented the Kaiba koseki that recorded the dissolution of Seto's adoption in the Kaiba family, the change of Seto's surname, which would prevent him from gaining future rights to the company, and the change of Shizuka's surname, allowing her to remain in the company's management as the new Vice President and take her only son Shinji in. Shizuka remarked that everything will fall into places where they should have been; at least she would be part of the family as Seto would have wished ever since they broke up and Shinji would be home because he was Seto's son after all. Seto's face was changed from total resignation to complete shock after hearing the last thing that Shizuka said.

Shizuka told Seto the truth that Shinji was conceived before they broke up and the fact came to her in a terrible time when she left for America and Seto and Mokuba began their power struggle for the company. Because Shizuka was in favor of Mokuba taking over, she didn't say anything to Seto and continued to raise Shinji on her own while completing her MBA in Columbia University. Pavel Chekov helped her in raising Shinji and acted as a surrogate father to Shinji in the first years of his life, but Shizuka had been faithful to Seto, in hopes of returning to him. When Mokuba came to know about Shinji, he told Shizuka to remain quiet about Shinji until he took over the company and Shizuka agreed to protect Shinji from Seto who may use him to maintain his control and corrupted leadership.

After apologizing for not telling Seto about Shinji sooner, Shizuka mentioned Mokuba's gratitude and acknowledgment of Seto's efforts to raise him and told Seto that he could do better with Shinji. Seto got provoked when Shizuka told him her reasons, saying that she just said that to make him suffer in retaliation for what he did to Shinji. Shizuka resolutely requested Seto to apologize to Mokuba, even if it would be for the last time, and do the next right thing or he would regret it for the rest of his life just as she did when she believed in a man like him and Shinji had to believe in God as the only father he will have. As a heartbroken Shizuka walked away, Seto was angered with Shizuka letting Mokuba brainwashing her and mentioning a God that he never believed in and violently struggled in his straitjacket until he was restrained and drugged by the nurses. While elated after hearing about the existence of his grandchild, a tearful Stefan was both reminded of his last fight with his late wife Tomoka regarding his abandonment of Sharon and devastated by his son's mental suffering and separation from his family like what he went through for twenty years.

A Painful Reunion
Stefan was visited by Maximillion Pegasus and the International Criminal Court officials to retrieve the cards. Wanting to protect his sons one last time, Stefan gave the rare cards to Pegasus and testified to the International Criminal Court that even though Seto was the true perpetrator of these crimes, he decided to turn himself in Seto's place because of Seto's mental condition and the reasoning of the blood contract. In the contract, it stated that if Seto’s relation to Stefan is known to others than him and Gozaburo, Seto’s blood will be shed in Stefan’s liability. Choosing to spare him after the relation became known will be suicide; in sum, Stefan will be shed in Seto’s liability. Stefan spared Seto’s future behind bars by taking full responsibility for the death of Ambassador Long, which was under Seto’s liability. The ICC took word of Stefan’s choice and arrested Stefan. Shocked to his father's choice, Mokuba was forced to say goodbye to his father again after a short time. To everyone's dismay, Stefan allowed the International Criminal Court to take him in, and Stefan was sent to the Hague in the Netherlands.

The Hague
While in The Hague, Stefan had to remove his metal prosthetics, which reminded him greatly about his auto accident that separated him from his sons twenty years ago and triggered his severe emotional breakdown that released his feelings of anger and shame that he held for more than twenty years of his lifetime. Losing nearly his will to live, Stefan hadn't spoken and eaten for weeks. He started to see how corrupt he became since he rose to power with his ambition and determination that blinded him from the sufferings he caused to his family, especially his late wife and his own children with his firstborn being close to horrible as him.

Father to Daughter
Convinced by Pierre and her mother Lena, who was an old friend to Stefan and the deceased Lady Tomoka, Sharon visited her father at the Hague, and Stefan told her that he regretted that he left her at the orphanage years ago and disregarded her because of his mistakes. Ever since he left her in the orphanage, he had been guilty for leaving her behind that his mistake began to haunt him ever since he lost Seto and Mokuba to Gozaburo and he invested his attention on Seto more than her who needed him more than him. When he saw how terrible Seto was to Mokuba and then to her, it broke his heart to see his own children treat each other because of his lack of presence and accountability. He told Sharon the truth that he disowned her so she would follow her principle to do the next right thing, instead of his own; he knew that his time was up in the company and he needed to make up with his family that the only way to do without compromising Vasily's willpower to fight was to end the proxy war against Vasily with Sharon's shares that were the exact amount that Vasily needed to take over the company.

While he stated that Gozaburo was a terrible man to raise his children, Stefan acknowledged that he had done terrible things as well and due to his lack of insight, Seto would had been the same terrible person he was if he would raise him. Sharon told him that she never believed that would be true. She revealed a memory that she almost forgot; she told him that a kind lady, who was the most gracious person she had ever met, revealed herself as the mother who could had raised her but she couldn't because she was sick while she was bearing her child. After sharing some times when her husband was a good person who cared about his family, she finally told her and Pierre in the orphanage, "While some children are unfortunate to bury their parents, no parent would want to bury their own child." When Sharon showed him a photo of Tomoka with her and Pierre at the orphanage, Stefan realized that the lady Sharon was talking about was his wife, and Sharon told him that if Tomoka was the kind, gracious person as he deemed her to be, she wouldn't want to see her own husband punishing himself. After many years of estrangement from his daughter, Stefan finally reconciled with Sharon and moved forward from his feelings of shame and guilt he had felt for so long.

Reunion with Seto and Release from the Hague
Seto’s 3 month stay in the psychiatric ward had expired, so Seto was cleared from the hospital but subpoenaed for his personal appearance in the trial for his misdeeds in the past, specifically for his involvement in the forced suicide of Ambassador Zhou of Hong Kong. A week before his last day, the Kaiba family's trusted doctor and father of Tsubasa Sasaki (the Chief Research Officer after Pierre resigned), Dr. Sasaki checked on Seto per Mokuba's orders and disclosed Mokuba's medical condition that Mokuba never spoke about to Seto: Mokuba was actually HIV positive, not due to gay sex but due to sexual abuse afflicted by his stepfather who was actually HIV positive. When Dr. Sasaki revealed Mokuba's blood tests and records about his antiretroviral therapy starting when he was 15 years old, the same time when Shizuka was pregnant with Shinji, Seto was devastated with complete shock and Dr. Sasaki showed him a video recording of Mokuba's conference with his appointees as his new board of directors. As he watched Mokuba speaking, Seto stared in awe after he heard Mokuba saying, "Since day one, Seto had sacrificed both his mind and body to raise both me and the company. Since Father was away, Seto had sacrificed his heart piece by piece until he couldn't feel pain and loss. Before it would be too late, Seto must retire in order to prioritize more on his family than the company with the remaining pieces of his heart that he has left. It's about time for me to return the favor by taking my therapies for my illness to the max and investing all my life and energy I have left in the election God has given me and the company my brother had left me."

A tearful Seto realized that Mokuba was actually sick during the power struggle but he was still fighting and willing to sacrifice himself because he wanted Seto to prioritize more on Shizuka and Shinji than the company: Since day one, Mokuba had been loyal to Seto, even up to the point of illness. After knowing how much he hurt other people, including Mokuba, Shizuka and Shinji, Seto responded to the civil subpoena forwarded by the ICC and called Pavel Chekov from New York to visit him before his departure. Seto sincerely pleaded to Pavel that he wanted to see Mokuba, Shizuka, and Shinji for the last time because the chance of a life sentence in prison was imminent and if he would remain in prison for the rest of his life, Pavel would take his place in taking care of them. Even though Pavel was initially reluctant to accept Seto's last request, he agreed to let Seto see Shizuka and Shinji soon.

Seto was transferred to the Hague for the trial, where he reunited with Stefan and apologized that Stefan had to step in this situation because of his greed, kneeling before him. When Seto told Stefan that he failed as a brother that he couldn't face Mokuba any longer and as a father that he couldn't even face his own son, Stefan, who once felt similar shame and guilt to himself, reassured that Shinji would always be in good hands because Seto raised his brother who turned out to be a better and stronger man than himself, revealing that he knew about Gozaburo's abuse of Mokuba from Oskar and the connection to Mokuba's illness that he learned through Isono. Both Stefan and Seto went on their way to the lobby and encountered Mokuba. Stefan revealed to Mokuba that Seto knew about the truth about his illness, and a guilt-ridden Seto was into tears and embraced Mokuba as he apologized to him for his cruelty and berated him for delaying the truth because of their shared sufferings from their stepfather. With Mokuba's guidance, both Seto and Stefan saw Shizuka with Shinji, who was able to see after his successful operation. When Stefan told him to go to them, Seto refused to reunite with them until he could be the father Shinji deserved without any more guilt and shame.

Gaining Sharon as his attorney, Stefan was granted a trial. Since Pierre permanently retired from law and returned to his medical work in New York, Pierre contacted Yoshi-san, who was the General Counsel of Kaiba Corporation after Pierre resigned, to execute a settlement for the Zhou family. With Pierre's full support, Sharon freed Stefan from the Hague, arguing that there was a lack of reason to prosecute Stefan for murder because of his amiable relationship with Long Zhou and Seto's mental illness and their requests to dismiss the case with the fully executed settlement from Kaiba Corporation and Trifonov Corporation. When questioned about Stefan’s contract, Sharon stated that Stefan’s contract was void in origin due to unlawful consideration and Stefan’s reasoning of the contract was faulty because he was under duress.

A penitent Seto formally declared that although he was mentally suffering for years since he took over Kaiba Corporation ten years ago, he was still guilty for the death of Ambassador Zhou because of his obsessions with the Blue Eyes White Dragon, who he considered as his personal savior and the only reminder of his father who he thought he lost. He acknowledged how much he hurt others, including his family, and how much he deserved to be punished in the harshest way possible.

When Pierre was subpoenaed to appear as a witness to the false accusation of Joe Cord for larceny, Pierre truthfully told his account of the event, and he added that while Seto had committed vicious crimes to others for his selfish reasons, Seto was the only family that Mokuba had left ever since they were separated from their father and if Pierre wouldn't spare him after saving Mokuba that night, Mokuba would be alone. He remarked that Seto acted without mercy due to his lack of knowing mercy because no one, even fate, had ever granted him any form of mercy in his life, and even after Seto tried to kill him twice, he already forgave Seto.

Before the final verdict, Xi-Li Zhou, the second son of Zhou and one of Katsuya’s engineers who was subpoenaed to appear as a witness, stood up and declared that his father knew how valuable the card was, not because of its rarity or power but because of its personal significance to him. The card was given to him out of brotherhood between Stefan and Zhou when they were military comrades and eventual business partners. According to Xi-Li, Zhou was a forgiving, compassionate man who saw Seto as a pitiful child who had to lean on power when he had nothing to lean on. Xi-Li knew what it was like of losing a father and struggling to find a purpose in life. In his late father’s name, he already forgave Seto. Stefan saw an apparition of his late friend smiling, implying that he would have done the same thing.

From everything that was gathered, the International Criminal Court permanently cleared their charges with Stefan, whereas Seto was sentenced to 5 years in prison in Japan due to provocation from his official diagnosis of paranoid schizophrenia, evident remorse, and the fully executed settlement with the Zhou family. Stefan was released and Seto was transported to Fuchu Prison back in Japan, where he was incarcerated for 5 years for the bribery with Boris, the attempted murder of Pierre, and the defamation and false imprisonment of Mokuba. Stefan, Shizuka, and Shinji were both relieved for a shorter sentence for Seto. Pavel agreed to take care of Shizuka and Shinji until Seto would return only in one condition: Even if Pavel would do whatever it takes to take care of them, he could never replace Seto because Seto is Shinji's true father and Shizuka's true partner in life.

Even though Stefan grieved to see his son going to prison for his wrongdoings, Dmitri reassured Stefan that Seto did the right thing for denying himself and taking accountability for his wrongs, and Stefan knew that he couldn't protect Seto from learning from his mistakes. Stefan started to think that if it wasn't for Pierre's influence in his family, his family would remain in darkness and Seto wouldn't see the errors of his ways. After acknowledging that, Stefan found closure with Katerina, considering Pierre as a miracle and thanking her for her sacrifice, which was the same as Tomoka after giving birth to Mokuba. After Stefan finally reconciled with Dmitri and gave his late blessing to Pierre, Stefan parted ways with the Smerdyakov family and returned to Japan, obtaining the closure and inner peace he yearned for a long time. He also decided to join bible studies from Mokuba's invitation.

Epilogue
In the beginning of his retirement, Stefan decided to take part-time care of Shinji with Pavel during Seto's incarceration because Shizuka and Mokuba worked full-time managing Kaiba Corporation. When Trifonov Corporation was merged with HI Engineering since Katsuya's induction as Chief Sustainability Chair, Katsuya decided to be the executive producer for the second adaptation of Shiro-san's Cafe to support HI Engineering and TC's joint campaign in educating children about the sciences and current social issues like climate change and global warming while teaching life lessons and healthy lifestyle tips. While Stefan and Vasily became executive producers, Shinji and his cousin Yujyo became co-stars of the show. Stefan ensured that Seto was able to watch the show while in prison, so Seto wouldn't miss out on Shinji growing up. When Seto came out of prison after 5 years, Stefan arranged Seto to meet Shinji after a day of shooting and almost teared up when he saw his son coming out clean and starting things over because he knew that Seto was in Shinji's age when he could had been with him, finding complete peace with his painful past.

Deck
Stefan valued power and strategy, which was shown through his preference of Trap Cards and Dragon-Type monsters to dominate over his opponents.

Stefan's first deck was the deck he used while he was representing Russia as the High King of Dragons until his retirement from the dueling ring. This deck was a combination of the Blue Eyes and the Power decks, which consisted the four copies of the Blue Eyes White Dragon in the world and Blue-Eyes Ultimate Dragon and Blue-Eyes Shining Dragon (his signature card), numerous Dragon-Type monsters, and other cards that aid and protect Dragon-Type monsters like "Den of Targaryen", "Silver's Cry", "Call of the Dragon Lords", "Stamping Destruction", "Dragon Rage", "Wingbeat of Giant Dragon", and two cards that he created himself, "Mother of Dragons" that had the special ability to Special Summon any Dragon-Type monster from the Deck on the field and be equipped to the summoned monster and "Night's King" that had the special ability to Special Summon any Dragon-Type monster from the Graveyard on the field and be equipped to the summoned monster.

When he participated in the KC Championship of Legends, Stefan was using his current Tolkien Deck with powerhouses whose attack strengths were rivaled by the Blue Eyes White Dragon:
 * "Galadriel the Lady of Light (ATK: 3000 / DEF: 2500)" (whose Effect was to increase 500 attack points for every Light Type Monster on the field)
 * "The Witch-King of Angmar (ATK: 3000 / DEF: 2500)" (whose Effect was to prevent the Effects of Monster Reborn on every monster that was destroyed by it)
 * "Fellowship King Aragorn of Gondor (ATK: 3000 / DEF: 2500)" (whose Effect was to gain 200 attack points for every Warrior-Type Monster on the player's side of the field).

As a man of strategy and power, Stefan, like his son Seto, uses dueling techniques that beat down to his opponent's source of power, including the use of "Galadriel the Lady of Light" and the spell "Diffusion" to destroy Light Type Fusion Monsters (like Seto's "Blue Eyes Ultimate Dragon"); the use of weak "Orc" monsters as bait to activate "Crush Card Virus" and destroy every monster above 1500 attack points in his opponent's deck; the Summon of "The Witch-King of Angmar" and destroy powerful monsters; and the Ritual Summon of "Fellowship King Aragorn of Gondor" and the Special Summon of "Army of the Dead" with the Equip Spell "Anduril the Flame of the West" to destroy every monster on the opponent's side of the field. Unpredictable as he could go, Stefan was also known for his quick improvisation and power in his strategies to confuse his opponents that he can defeat his World Champion son Seto Kaiba and the only person who can outmatch his skills was Yugi Muto of Japan.

With normal trap cards, like "Crush Card Virus", and spell cards, like "Grace of Charity" and "Diffusion", Stefan's Tolkien Deck included its wide range of Spell and Trap Cards.

Parents
"Stefan is not just royal in looks and noble in wisdom; he was born with it. His mother was a Princess in the House of Gagarin until the Revolution, while his father was a noble craftsman who had a fortune from creating priceless trinkets for the imperial court. Too bad that they lost so much value after that. - Dmitri Smerdyakov on Stefan's royal parentage"Stefan was the second eldest son of Princess Alexandra Nikolayevna Gagarina of the Gagarin House in the Rurik Dynasty and Count Vyacheslav Vladimirovich Trifonov. Stefan had a good relationship with his parents. After his older brother, Viktor, died during the onset of WWII, Stefan took care of his mother until her dying days, and he worked with his father in the Siberian mines until his father died in an explosion in the mines.

Viktor Trifonov
"About our beloved Vitya, I can describe him in five words: He died for his country. - Stefan on his older brother Viktor"Stefan's older brother Viktor died during the onset of WWII before Stefan was born, becoming the brother Stefan never knew. When Viktor knew his brother’s incoming birth, however, Viktor fought his hardest and sacrificed his life in the war to make the world a better place for his brother to live in, even when he knew that he was going to die in honor. Before his final moments in the world, Viktor wished the safety and security of his people, especially his unborn little brother, and promised to go straight home after the war was over to see him. When Viktor died at the end of the war, he asked his comrade Dmitri Smerdyakov to watch over his family for him and tell his brother the reasons why he died through a letter. Finding a second family in Viktor, Dmitri decided to fulfill his fallen comrade’s dying wishes by watching over Viktor’s family, especially Stefan and Vasily who he personally raised. Later on, Dmitri showed Stefan a photo of him and his older brother and read Viktor’s letter to him. After realizing that Dmitri lived longer than he thought and knew Viktor personally, he acknowledged his brother’s death in action and respected his brother more.

Vasily Trifonov
"The more I agree with him, the more I regret without him. - Vasily and his different interests with indifferent Stefan"Vasily Vyacheslavich Trifonov was Stefan's younger brother. Even though they had an age gap of 13 years, they remained to be very close after their parents passed away. Even though the upbringing of Vasily was stressful after the death of his mother, Stefan continued his education and job as a civil servant to maintain a stable livelihood for Vasily, and in turn, Vasily had always respected him as a head of the household. Initially out of debt for raising him, Vasily's loyalty gradually turned into a fear of him until he decided to fight back.

Once Vasily turned 18, Stefan decided to let Vasily join him in many of his adventures. Stefan joined the Russian Airborne Troops with his brother, where they always did dispatches together to ensure each other's welfare. When the Russian Airborne Troops secured their posts in the Russian Aerospace and Defense Force, Stefan and Vasily received their B.S in Aerospace Engineering in Moscow Aviation Institute and MBA in INSEAD. After their retirement from dueling, Stefan and Vasily created Trifonov Corporation together, making the elements of brotherhood and fraternity great foundations to make the company one of the most successful in the world. When Stefan had children, Vasily had loved and taken care of his nephews and niece.

When the brothers were discussing their opposite philosophies about power and potential, Pegasus recruited and collaborated with them to create the game of Duel Monsters with him. While Stefan created the Blue Eyes White Dragon to represent power, Vasily created the Red Eyes Black Dragon to embody potential. While Stefan created Trap Cards to add strategy in the game, Vasily created luck-based cards to add chance. Later on, Stefan and Vasily built the Statue of Brotherhood (the statue in front of the Trifonov estate in Hokkaido) together, showing the two dragons to represent their brotherhood and their love for their creations and the game itself. While dueling, Stefan and Vasily played as a tag team, which was known to be one of the most powerful in the world of Duel Monsters. Even though they were opposites in many ways, Stefan considered Vasily as his confidant and best friend, and Vasily loved Stefan as his best friend and supporter. Vasily had always been loyal to his brother, and he stayed true to his promises to keep his and his brother's dreams a reality through the successes of Trifonov Corporation.

Besides as his great strength, Vasily's loyalty to Stefan was also his great weakness. Vasily was strengthened by his bonds with other people like Dmitri, Adina, and especially Stefan who Vasily felt that he owed a debt to him. Stefan gradually became an authority figure to Vasily during their days in Russia that Vasily was hesitant to help Dmitri because of Stefan's discord with him. Stefan took advantage of Vasily's loyalty to purposely put him into a great fall when he took over Trifonov Corporation because of his anger of Vasily for placing a succession on a non-member of the Trifonov family who he personally viewed to be an underdog and he knew that Vasily wouldn't fight back because of his unscathed loyalty and debt to him. Instead of fighting back, Vasily initially was hesitant on standing up to his brother until he realized that he had lived in regret by not standing for what he believed in and he had to take a stand for his beliefs before the future of Trifonov Corporation and their shared legacy would be ruined. When he took a stand and knew that it would cause entrenched management, Vasily took advantage of Stefan's confidence of his secret relation to Seto, and he made an elaborate plot of overthrowing Stefan with negative publicity and succeeded in taking over; however, Vasily was surprised that Stefan officially stated his concession and he was planning to concede before the takeover because of what happened to his family.

There were many running gags in their relationship. One of them was that Vasily had always been reprimanded by Stefan for his playing craps with real bets and being a glutton on Adina's desserts, while Stefan had always been reprimanded for his being a workaholic and being a glutton on meat. Another one was that Stefan used to call him "Hokey Pokey", "wannabe", or "dweeb" whenever Vasily had done something out of stupidity, while Vasily used to call him "Prima Donna", "queen bee", or "diva" whenever Stefan was giving him too many orders. At one time, Solomon Muto compared the two of them with the Kaiba brothers when they were loving each other, and then, he compared the relationship between them with that between Seto Kaiba and Joey Wheeler when they were reprimanding or insulting each other. The quirks of this hate-love relationship between the brothers eventually gave Yugi and Solomon the idea that Seto and Joey could be friends in the same kind of relationship that Stefan and Vasily shared because of their numerous similarities with the brothers and themselves.

Adina Trifonov (née Acardi)
"If you want help, ask Stefan. He had the same sinking feeling when I was getting married to Adina. I may assume that he'll say the same thing about this kind of situation: Choose what is best, not what is easy. - Vasily on Stefan's initial discord with Adina"According to Vasily, Stefan had contempt for Adina when he first met her. Stefan initially saw her as an Italian bimbo who was only known for her appearance, rather than her intelligence. Adina, in turn, saw Stefan to be a contemptuous bully whose tongue was sharper than his mind. Even though they were on disagreements at some points, Adina still loved Vasily, no matter how hard Stefan tried to dissuade her. As a last resort, Stefan told Adina of Vasily's six failed relationships and his impotence, which could potentially narrow Adina's chances of having any children with Vasily in the future. Adina adamantly told him that she could adopt a baby or child and Vasily could be a better father than any other man she had met. Upon hearing this, Stefan changed his mind about Adina, and he started to respect her by trusting her to be the Head Secretary of Trifonov Corporation. Adina let bygones be bygones between her and Stefan by taking care of his sons Seto and Mokuba and raising his daughter Sharon.

Vincent Trifonov (née Noah Kaiba)
"I may be a Kaiba, but I decided not to take a name of treachery. I thank Uncle Stefan for that. - Noah's gratitude for his new life"Stefan initially knew Vincent as Noah Kaiba, the sole heir and biological son of Gozaburo Kaiba. Stefan once saw him as a spoiled brat who lacked merit, but he took pity on his later situation when Vincent was digitized that he eventually created an in vitro body for him. Stefan once relished on the idea to take Vincent as his own son like how Gozaburo did to his own sons, but he decided to give Vincent to Vasily and Adina after realizing how they longed to have a child. Stefan was impressed with Vincent when he graduated from TIARA and worked in Trifonov Corporation as Chief Business Officer and later Vice President with his father. Because Stefan altered Vincent's memories of his past life, Vincent only recognized Stefan as someone he owed a life debt.

As the new brain in Vincent's body started to develop over time, it gained a separate personality as "Vincent" that caused conflicts with his "Noah" personality and sometimes meltdowns in the presence of things that may remind Vincent of his past life; thus, Stefan prohibited him to go to Osaka because Kaiba Corporation was a huge part of Vincent's past life as its biological heir. Not knowing that "Noah" was a duelist before, however, Stefan allowed Vincent to play Duel Monsters, and Vincent was proven to be great at the game that he became a regional champion that allowed him to participate in the Championship, a suspicious factor to Stefan who taught his own son Seto the game and noticed how more equal Vincent's skills were to Seto. Stefan's suspicions proved right that Vincent had a strong reaction when he encountered a Spirit Monster deck, especially the Ritual Monster card "Shinato, King of the Higher Plane". Thus, Stefan created decks to minimize the strong reactions emitted from Vincent's alternate personality.

When his adoptive father and Stefan fought for power and control of Trifonov Corporation, Vincent was on Stefan's side because of his debt to Stefan for giving him a body, and Stefan took advantage of Vincent's debt that Vincent accidentally mouthed Vasily's tactic to gain shareholders and supporters that he took advantage of this and planned to take down Schroeder Corporation and Vasily by placing Skander as his "son" to rebuff the press. Due to his loyalty to Stefan, Vincent was then given the royal treatment in the company, but he became more lonely for that he was forced to hide his secret relationship with Roman Razumikhin and go against his adopted parents who treated him as his own son more than his creator can. His loneliness grew when he found out that Roman was apparently murdered at the eve of the tournament.

When Vincent came to know more about Skander and started to feel sorry for him, Vincent started to ponder about his loyalties with a man who would put Skander's life on the line and grew feelings of guilt as Stefan's plot progressed. In turn, Skander became more furious on how Stefan treated Vincent as a lap dog that he switched the deck that Stefan reserved for Vincent with a Spirit Monster deck with "Shinato" that Katsuya (who overheard the conversation between Boris and Stefan about Vincent's origins and remembered Vincent as "Noah") and Vasily created and hid in Skander's room. When Vincent used a Spirit deck to duel against Yugi in the quarterfinals, he was starting to remember and realize that he was once a Kaiba when he dueled Yugi previously and realize in complete shock that his biological father was Gozaburo Kaiba who betrayed him by using him for his selfish goals until he placed himself in a backup file and destroyed the supercomputer with Gozaburo's consciousness still inside. Recalling his whole life, Vincent realized that "Noah" would never want "Vincent" to be used and abandoned like he was back then, and after remembering his happy moments with his adoptive parents and his boyfriend, he decided to make things right and live a life that both of them desired to live. Deciding to be loyal to his conscience over his own creator, Vincent reconciled with Vasily and gave his shares to him. After knowing about Vincent's independence from him and autonomy with his personalities, Stefan let Vincent to make his own choices, especially after remembering Gozaburo's past life.

Wife
"We were married for ten years. About growing old, we did that…but not too long enough like I hoped for. Even though she was sick, she lived life as if it was easy. - Stefan on his first and only wife, Tomoka Seiku"Even though Stefan was available to every other Russian woman during his time as a bachelor and the President of Trifonov Corporation, especially Katerina Ivanovna Yaroslav who he was formerly arranged with and Lena Chernyavska who he had respect for her as a colleague, Tomoka Saiku was the only love of his life. Even though he was a foreigner, Tomoka was nicer to him than others in Japan, and she was willing the culture and language with him because the first thing he did by the first time he met her was asking for her name, while other men became attracted to her beauty and attempted to hit on her before knowing her personally. While learning the culture and language, Stefan became attracted to her by her intelligence and gentleness, while he was infatuated with her beauty second to her personality. In spite of their age gap, Stefan became her danna until their marriage became official and Tomoka had to retire.

Once married to her, he was willing to be sacrificing for her and her children. Even though many women were attracted to Stefan by his looks, intelligence, and wealth, he had remained a faithful husband to her and a great father to their sons. When Tomoka's condition became terminal, Stefan devoted most of his time to the welfare of his wife and son, in spite of the increasing pressure from Kaiba Corporation and liability from Trifonov Corporation. When Mokuba was born, Stefan grieved for their mother's death, but he perceived his son's miraculous birth as Tomoka's last sacrifice for her children. In her funeral, Stefan wore normal clothes, instead of black clothes, as his unique way of showing that while he never stopped loving her, he never stopped being happy and proud of her for her sacrifice for their children. After losing his sons to Gozaburo, he grieved for his wife even more that he experienced hallucinations of his wife and dreams of his past life as a husband and father, aggravating his severe depression.

Sharon revealed to Stefan that Tomoka visited the orphanage and told her about him as a loving father to his children. Tomoka saw Sharon as her own daughter because of her unconditional love for Stefan and compassion for children. Tomoka once fought with Stefan about his lack of responsibility and custody of Sharon that her last words included a request to take Sharon back to the family, which was one thing she wished to do if it wasn't for her illness. Due to his extreme feelings of shame and guilt for having to leave his sons behind, Stefan only honored Tomoka's wish by word, not by action; he took Sharon in but left her in the custody of Vasily and Adina. Sharon and Lena remarked that if Tomoka was the kind, gracious person Stefan knew, then she would not approve of what he did and let her own husband punish himself.

Children
"Child! I knew those tactics not only because it was I who made you every card and trick about this game but because it was I who taught you everything you know about every game. Now you know who I am... my son?! - Stefan revealing his true identity to Seto"

Seto and Mokuba Kaiba
Seto was his firstborn child with Tomoka and Mokuba was his third child (second with Tomoka). Even though he favored Seto due to many similarities with him, Stefan was very close with both Seto and Mokuba because they were also remainders of his late wife who died giving birth to Mokuba. In turn, they loved their father very much. Even though he was very close to his children, he never told them who he truly was as the President of a successful conglomerate because he didn’t want his children to be targeted by Gozaburo Kaiba and he wanted his children to obtain their own greatness. Even though Stefan can truly see a prospective heir in Seto, Stefan wanted Seto to live with a happy childhood and know more about respect and responsibility than pride and power. Stefan technically decided that Seto was not fit to be the heir of Trifonov Corporation due to his lack of social skills and his preference of technology over people. In spite of Stefan's absence in his later life, Seto lived up to his father's teachings of responsibility by taking care of Mokuba, and he unknowingly lived up to his father's image as a champion duelist and the CEO of a very successful company; however, Seto also took his father's ruthless and competitive personality and arrogance, which made him more greedy and self-absorbed.

Stefan had always acknowledged Seto's academic ingenuity and his love of games, especially chess and Duel Monsters. While they bonded through chess, Seto was revealed to be Stefan's first student in Duel Monsters when Stefan taught him the basics, and Seto taught Mokuba chess and Duel Monsters. Stefan told him about the Blue Eyes White Dragon, which made Seto and Mokuba very obsessed with the Blue Eyes White Dragon after seeing Stefan's painting of it. The primary reason why Seto and Mokuba were so absorbed with the Blue Eyes White Dragon cards was that the card was the last thing that they could remember of his past family when they were forced to forget everything of their previous lives as Stefan’s children by Gozaburo and their old toys were confiscated during his accelerated studies under Gozaburo's direct supervision.

In later years, Stefan sacrificed most of the time of his life to protect his sons who were forced to forget their past and their first family. Even though Stefan wanted to prevent Gozaburo from tearing his family apart and raise his sons with his family in Russia, he was willing to sign the blood contract to let Seto and Mokuba to take the Kaiba family name and prevent Gozaburo from killing them any further, even if it means not to contact them or come back to Japan. Even though he obliged to confiscate the rare cards and turn in Seto to the ICC for the crimes he committed against his associates and their families, he was willing to submit himself to the International Criminal Court to prevent his son going to international jail until Seto turned himself in and went to prison for his actions, which was off-limits to Stefan's protection as a parent. Throughout his years of absence, Stefan learned about what Seto had become to others, and Stefan had great concern for his son's greed for power and his potential of becoming like Gozaburo. He also used the KC Championship and the business gala to bond with his sons once more, and he used his duel with Seto to correct him for his wrongdoings to his former associates and his greed for power and confiscate the cards as punishment.

Seto and Mokuba hadn't learned their father's true identity until the truth was revealed to them (Mokuba learned it before Seto). While Seto was a bit skeptical, Mokuba believed in the truth. When Stefan returned, Seto and Mokuba were overjoyed to see him again, and they bonded with their father after many years.

Stefan also didn't like anyone who attempted to disgrace and hurt Seto like Gozaburo who attempted to euthanize Seto as a means of revenge and Skander who attempted to impersonate Seto and assault the genuine article.

Sharon Stefanovna Trifonov
"I was trying so hard to be perfect before my father, but I was nothing compared to Seto, no matter how much I tried. - Sharon on Stefan’s contemptuous treatment of her" Sharon was the illegitimate child of Stefan and his former employee, Lena. Stefan once felt ashamed to bore a child out of rape, up to the point when he decided to leave Sharon to the orphanage. After losing Seto and Mokuba to Gozaburo and being deported from Japan under the blood contract, Stefan saw this dark hour as a punishment from God for his shame and inability to raise Sharon rightfully and decided to take Sharon in from the orphanage. Because of his inability to cope with the loss of Seto and Mokuba, however, Stefan wasn't very close to Sharon, so Sharon was raised by Vasily and Adina instead, who were more like parents than just relatives to her. Even though Stefan wasn't close to Sharon like he had with his sons, Stefan was very impressed with her financial independence and success in her academics and the legal field. Nevertheless, Stefan saw her as a disposable child, in contrast to her half-brother Seto, and took advantage of her loyalty to maintain control of Trifonov Corporation.

Even though she greatly appreciated the love from her aunt and uncle, Sharon found her father very difficult to understand and bond with because of his aloofness; however, Sharon had been striving to please and reconcile with her father. Sharon thought that it was because of his stress at managing Trifonov Corporation, and she wanted to be close to him, even if it meant to work as his General Counsel. Until Stefan reconciled with the Smerdyakov family, Sharon was very annoyed of Stefan's contempt toward them, especially toward her fiancé Pierre who practically raised her in the orphanage and supported her all the way in her undergraduate studies at Harvard College and graduate studies at Columbia University.

Before Sharon knew Seto and Mokuba as her half-brothers, Sharon had a jealous streak when they were with Stefan, mostly towards Seto rather than Mokuba, when Stefan put more attention to Seto than to her in the business gala. Unfortunately, it got worse when she knew their relations with him from Pierre, and it got up to the point when she was in tears after Seto publicly humiliated her in their duel and Stefan practically "disowned" her by telling her to call him "father" after she learned how to win herself. It turned out to be a fatal mistake on Stefan's side when Sharon surrendered her shares to her uncle Vasily, enabling Vasily to take over Trifonov Corporation under her father's nose. When he told her to come to his side, she told Stefan to call her "daughter" after he learned how to humble himself. When Pierre told her about Stefan's true intentions and his detention in the Hague, Sharon decided to let her resentment go and free her father with Pierre. Sharon reconciled with him before freeing him.

Smerdyakov family
"The Smerdyakov family were all servants at birth, never once a master. - Stefan's blunt impression on the Smerdyakov family"

Dmitri Smerdyakov
"Don't mind that old piece of cheese. With his age, his face gets riper, but his comments stinks. - Dmitri joking on about his age" Dmitri raised Stefan and Vasily when they lost their parents and older brother. Stefan knew Dmitri Smerdyakov in his years at the KGB Academy, and the two were comrades. It revealed that Dmitri was older than Stefan, but Dmitri resembled someone in Vasily’s age due to his intake of the Kraven Serum that elongated his life for more than a hundred years. It was also revealed that Dmitri fought with Stefan’s older brother Viktor during Operation Barbarossa, and they were combat comrades until Viktor died by saving him from gun-shot. Dmitri promised Viktor that he’ll watch over his family and his little brother Stefan. After being moved to the KGB rankings, Dmitri watched over Stefan while he was growing up, even during the KGB years when he was a spy. Stefan and Vasily respected Dmitri as their senior mentor, but their reverence was proved to be short-lived. When Dmitri suffered exile for his failure as a special operation agent, Stefan held contempt toward him, considering his service to his country and later criminal life as dishonorable; however, he had sympathy (though a bit more superficial than sincere) for Dmitri's mental illness that he gave Dmitri's old friend Joe Cord an original copy of the Blue-Eyes White Dragon with the shared intention to give it to Dmitri and alleviate the pain he endured.

Dmitri was discontent with Stefan’s blunt and critical attitude to others, especially when Stefan bluntly described his old war comrade Viktor. When he insulted his late wife Katerina in front of Pierre, he attacked Stefan with uncontrollable force until Pierre restrained and calmed him down. In spite of his assertive behavior, Stefan was still shocked by Dmitri’s violent act because not only it reflected his attitude towards others and his differences with him but Dmitri’s strengths that were superior to his own, in spite of his identity as a criminal and a dishonorable discharge from the KGB. While Stefan was well-respected by others and supported by his family, Dmitri only had his son to help him. While he left Sharon in the orphanage due to his shame, Dmitri left Pierre because of his love for him. In The Hague, Stefan started to feel what Dmitri felt when he was in prison and he was forcibly away from his family and friends that he lost for many years of his lifetime, and Stefan started to humble himself and prayed to God for his freedom. After Stefan was freed from the custody of The Hague, Stefan and Dmitri reconciled.

Pierre Smerdyakov
"Your need of humility comes way too high a cost than your own face. - Pierre while standing up to him"Stefan's relationship with Pierre was more like a more-hate-than-love relationship. Stefan met Pierre for the first time in the orphanage when three-year-old Pierre decided to take care of Sharon when she was an infant. He was impressed with Pierre's intelligence and maturity at a very young age that greatly reminded him of Seto. Pierre, at that time, was forgiving, but he was still angry at Stefan for choosing to disown her out of shame. That was how Pierre found a new respect to his own father: while Stefan did that out of shame, Dmitri gave his chances to live with Pierre out of protection.

When Stefan discovered that Pierre was Dmitri's son later in life, he held great contempt to Pierre because of him being everybody's servant and nobody's master like his father, much to Sharon's annoyance. He even used other ways to put Pierre down. Even though Pierre was both a doctor and a lawyer, which was extremely rare yet achievable by a selected few, Stefan considered him as indecisive with his life and unjustly spat that he should make up his mind. Because Stefan knew Pierre's blood relations with the Kravenoff family through Dmitri Smerdyakov, he was reluctant to bless Pierre's marriage to Sharon and let Sharon be connected to a dishonorable family. Stefan had no qualms on publicly humiliating Pierre by callously calling him "servant boy" in front of Sharon and everyone else. In turn, Pierre was disgusted for Stefan's attitude toward Sharon, his father, and his family, but his forgiving nature made him willing to let his negative vibes go for he was the first one who had a thought about freeing Stefan from the Hague.

Stefan, however, was immensely impressed with Pierre's dedicated work and positive influence in New York and later in Kaiba Corporation, which reminded him a lot of himself. Even though Stefan firstly regarded Pierre as someone from a disgraceful family, Stefan felt that if it wasn't for his mistakes, Seto and Pierre could be best friends and Seto would be a different person among other people.

Kravinoff family
"Even as of royal blood, I never supported them. They can be savage like lions in a pride. - Stefan on the Kravinoff family"As a member of Russia's social elite, Stefan knew Sergei Kravinoff and his wife Sasha. While interested in Sergei because of his longevity, Stefan was disgusted with Sasha for her gold-digging reputation and her patricide under her support for the White Russians. They totally lost Stefan's favor when they were also criminals in America. Stefan's lack of respect to them had passed down to their children. When Stefan came to know that Vladimir, the firstborn son of Sasha Kravinoff, was working for Schroeder Corporation and noted his vague resemblance to Seto due to their similar height, Stefan used Zigfried's plan that involved Vladimir as a decoy corporate spy to undermine Schroeder Corporation and reveal his true identity as a wanted fugitive, but the plan backfired when Isono spared Vladimir after the trial. Vladimir saw Stefan as a male counterpart of his mother, except more cunning and devious. Ana also came to know him, since she attended Acardi Academy for Girls, which was owned by Stefan and his company, but their interaction was far too little as compared to her brother. Alyosha was the only Kravinoff sibling who never had interaction with Stefan due to his upbringing in Africa and residence in Australia.

Chekhov family
"Stefan himself was a friend to Father since Father had so many connections among the military. We admired him and his brother since we were kids. - Ivan and Pavel on Stefan and their father's friendship"

Anton Chekov II, PhD.
Stefan and Anton Chekhov II had mutual respect and understanding to each other back in their earlier years. Their respect had turned down to neutral civility when Anton knew about Stefan's former arranged engagement to his close friend and first, yet unrequited, love, Katerina Ivanovna Yaroslav. While considering Katerina to be a empty basket due to her status as a former Black Widow and her apparent inability to bear children, Stefan also knew about the closeness between Anton and Katerina that he taunted him for his feelings for his distant cousin. Anton was disgusted by the way Stefan mistreated Katerina, similar how his son Pavel hated Stefan for the way the latter mistreated Sharon. Their relationship, however, took a positive turn when it was revealed to both of them that Pavel secretly took care of Shinji, who turned out to be Stefan's grandson through Seto.

Ivan Chekov
Ivan and Pavel looked up to Stefan and Vasily when they were children, but out of the twins, Ivan favored Stefan the most because of his determination that made him successful. Stefan, however, didn't initially return the favor because Ivan, a business journalist for the New York Times, was assigned to do a press coverage of the concurrent proxy wars in Trifonov Corporation and Kaiba Corporation, the business gala, and Skander's trial; however, he became more cordial with him and he was impressed with the discussion panel series that both Ivan and Pavel co-hosted with their NYT colleagues because Ivan would get to look up to better people than him alone.

Pavel Chekov
Back in Russia, Stefan came to know Pavel as a child prodigy in the Bolshoi Theater as a talented violinist and prime ballerino in the past, but he was known to be contemptuous to artists that time because of their ongoing struggle to make a living. In turn, Pavel disliked him due to his neglectful treatment of Sharon, who was his friend in the Bolshoi Ballet Company before transitioning to the Bolshoi Opera, preferring to look up to Vasily because of his sociable, warmer personality. Many years later, Stefan showed disdain toward Pavel's former promiscuous lifestyle. Stefan's relationship with Pavel had turned for the better due to Pavel's friendship with his younger son, Mokuba, and how Pavel made Mokuba a mature, independent person. Stefan also realized that Pavel was the one responsible for helping Shizuka to raise her only son Shinji, who was actually his grandson through Seto. When Pavel helped Stefan in raising Shinji during Seto's incarceration, the relationship between Stefan and Pavel improved.

Schroeder family
"I don't sponsor cheaters, especially those who attempt to destroy the technology that made Kaiba Corporation in the first place. - Stefan's warning to Zigfried von Schroeder"Dueling champions and businessmen Zigfried and Leon von Schroeder respected and idolized Stefan during his days as the European World Champion, and they were his students in dueling and hacking. After falling away from Kaiba Corporation, Stefan made a deal with Schroeder Corporation in Germany, the rival company of Kaiba Corporation, to help develop more resources for both companies in good faith that they would not undermine each other. Stefan had contempt in the way the Schroeder brothers were raised, but he had compassion for the family when the head of the Schroeder family was driven mad by his competition with Gozaburo.

Ever since Zigfried took over in his father's place, Stefan sponsored Schroeder Corporation with great support until it fell in grace. After he came to know that Zigfried and his brother used the skills Stefan taught them to cheat in the first tournament at Kaiba Land and disgrace Kaiba Corporation as a means of revenge, Stefan decided to set Schroeder Corporation up into a scandal that almost put Vladimir Kravinoff and Skander Zarubin into jail and place its business under jeopardy when Zigfried was repatriated back to Germany to face prison time for five years.

Stefan overlooked that Schroeder Corporation's power as a former ally could be used against him because of his treachery against them. When Stefan severed his sponsorship with the company, the Meinhardt family sponsored Schroeder Corporation out of genuine compassion and generosity and lost respect for Stefan by signing a motion of no confidence against Stefan, enabling Vasily to take over Trifonov Corporation.

It was unknown about how Zigfried reacted when his current business rival was the firstborn son of his longtime family friend, mentor, and sponsor.

Gozaburo Kaiba
"Both were competitive. Both were strategists. Both believed in merit. Both shared an ambitious drive, but those with like charges repel. - Roland on his account of the adversarial relationship between Stefan and Gozaburo" Stefan, who represented Russia, met his eventual business partner Gozaburo Kaiba, who represented Japan, at the World Chess Championship. The relationship between them was firstly one of respect and good terms that it led them to Trifonov Corporation's partnership with Kaiba Corporation, which was the first foreign exchange for both companies. Because of Stefan's high credibility as an engineer and businessman, Gozaburo found him to be a powerful ally and a valuable Director that Kaiba Corporation became a more competitive company than its rivals, namely its German counterpart Schroeder Corporation and its American counterpart Oscorp, and Kaiba Corporation had a diverse array of cutting-edge technology, including its supercomputers and satellites, since Japan's reconstruction after WWII and the end of communism in Russia.

In spite of accomplishing these achievements with Stefan, though, Gozaburo had intense distrust and envy with Stefan because of Stefan's popularity with the staff and the allegiance from Kaiba Corporation's material companies to him over Gozaburo. Because of Stefan's growing power, Gozaburo and the other Board of Directors feared that Stefan would have a growing chance to take over Kaiba Corporation and make it a part of the Trifonov corporate empire. Stefan denied such intentions for that he was content with his position as a Director and a leader of his own company that he worked so hard to create. Gozaburo, however, saw this as his means of appearance as someone more credible to lead Kaiba Corporation than himself, and he pushed Stefan to his limits to increase resources for the company to prove loyalty to him. Stefan, in turn, defied this because Gozaburo was pushing him to do the one thing he cannot do: Prioritizing his own power over the safety and supply of the other companies who supported him. Gozaburo sued him and his company, and Stefan severed all business with Gozaburo, causing a financial crisis to Kaiba Corporation and an economic crisis to Trifonov Corporation.

Another dimension of the animosity between the two business partners was their relationships with Lady Tomoka. When she was a senior maiko, Tomoka catered to many clients, especially those in the social elite like Gozaburo and his business associates, one of them being Stefan. In spite of his own marriage, Gozaburo wanted to take Tomoka as his mistress and become her danna; however, Tomoka was disgusted with his boorish personality and treatment of his wife. Nevertheless, Gozaburo still desired Tomoka to the point of obsession. On the other hand, Stefan was a bachelor in his home country, and he treated Tomoka with respect and care that Tomoka gradually developed feelings for Stefan, up to the point that Stefan became Tomoka's danna. After paying her remaining debts, Tomoka retired from the hanamachi and married Stefan in a private ceremony in Japan and another ceremony in Russia. When the marriage of Stefan and Tomoka was publicized, Gozaburo started to hate his business associate and do dirty tactics to "win" Tomoka back like bribing TC mole Boris Razumikhin a share of Kaiba Corporation to start a scandal that involved Lena, one of Tomoka's close friends, to project an extramarital affair and another scandal that made Stefan appear to take over Kaiba Corporation, which initiated the litigation between the two companies. When all plans failed and Tomoka passed away, Gozaburo's obsession didn't stop. When Gozaburo noticed his adopted son Mokuba's uncanny resemblance to Tomoka, Gozaburo displaced his obsession on Mokuba, who became a target to his routine sexual abuse, and the intensity of the abuse increased when Mokuba was revealed to be Stefan's son.

Gozaburo's enmity with Stefan didn't end there. Gozaburo and the Board of Directors initiated a bloodbath within Kaiba Corporation by terminating Stefan's loyal employees from Kaiba Corporation and Trifonov Corporation. Nextly, Stefan and his family became prime targets that Stefan suffered a major automobile accident that was a chain reaction of his assailants from Gozaburo, and his sons Seto and Mokuba were about to be euthanized after Gozaburo adopting them and discovering their true heritage. When Gozaburo was forced into a contract by Stefan to prevent Seto and Mokuba getting killed, his hatred for Stefan descended to Seto when he was planning to take over Kaiba Corporation, and it endured until his dying days.

In spite of everything that bereft any level of forgiveness from Stefan, Stefan had some pity for Gozaburo once he came to read Gozaburo's old diary that Lena got in her possession and learned about his enemy's past life. Stefan learned that Gozaburo was a closeted gay when he was young and was once caught with his male lover by his conservative father who forced him to break up, especially when Gozaburo came to know that he was HIV positive and his lover eventually died of AIDS. Gozaburo was bullied by his classmates and family that he became extremely focused in his studies and his takeover of Kaiba Corporation as his vengeance against his father who took his lover away. In spite of his arranged marriage, Gozaburo became enamoured by Tomoka when she resembled his lover while becoming attracted to Stefan at the same time. When Stefan took everything that Gozaburo desired, Gozaburo was reminded of his late father that he was determined to crush Stefan just as he did with his father. Stefan expressed his pity for his dead enemy's hatred by allowing Gozaburo's biological son Vincent to make his own choices.

Trivia

 * While he was the main antagonist in Mr. T, Stefan gradually became an anti-villain due to some of his cruel acts that were done from moral intentions and his full redemption in the end, in contrast to Sasha Kravinoff's one-dimensional character as a manipulative villainess.
 * With Stefan as Chief Research Officer, each member of the Big 5 (in this case, 6) represented a specific attribute of Duel Monsters (except the DIVINE attribute): Gansley being WATER; Crump being WIND; Johnson being EARTH; Nezbitt being FIRE; Lecter being DARK; and Stefan being LIGHT from his signature card, Blue-Eyes White Dragon. The Big 5’s signature card was the Five-Headed Dragon, which can only be destroyed in battle by a LIGHT monster. This represents the Big 5 losing power to Stefan before Stefan’s termination and his son Seto after Seto’s rise to power. Coincidentally, in the card’s first anime appearance in the original series, the Five-Headed Dragon was defeated by a variation of the Blue-Eyes White Dragon: Dragon Master Knight (the Fusion Monster of Blue-Eyes Ultimate Dragon and Black Luster Soldier, one of Stefan’s few non-Dragon Type creations to be affiliated with the Blue-Eyes Deck).
 * Besides the Blue-Eyes White Dragon, Stefan created other legendary cards associated with it and equal in power to it, including Ritual Monsters Paladin of White Dragon and Black Luster Soldier, Effect Monster Lord of Dragons, Normal Monster Mystical Elf, and Fusion Monster Dragon Master Knight. These cards were owned by his title successors Seto Kaiba and Yugi Muto.
 * Among the duelists featured, including those who retired, Stefan was the second oldest Duelist, after Sugoroku Muto who was in his 70’s.
 * Stefan was the third oldest character in Mr. S, with Sergei being the oldest and Dmitri being the second oldest, and the second oldest character in Mr. T (since Sergei Kravinoff died at the end of Mr. S). Amongst the heads of the four main families, Stefan was the youngest of the four, with Sergei being the oldest, Dmitri being in similar age to Sergei, and Anton being at similar age as Stefan but older.
 * Each of Stefan’s children inherited a specific skill of Stefan and they all inherited his interests in gaming and business. Seto inherited his technology skills. Mokuba inherited his drawing skills. Sharon inherited his singing skills.
 * Stefan and his eldest son, Seto shared the same birthday: October 25. Out of his three children, Seto mostly resembled his father in looks and personality.
 * Stefan's sleeping habit is derived by the Red King from Through the Looking Glass.