Judai Yuki

Saiyou Takuma and Rector Kagemaru: They are key characters with whom Judai has had confrontations that defined his destiny and the balance of the world.

Professor Chronos de Medici: Their relationship evolved from initial rebellion to deep admiration and mutual respect by the end of his time at the Academy. Professor Daitokuji and Pharaoh: He maintains a mystical bond with the spirit of his former mentor from the Slifer Red dormitory and his cat Pharaoh. Director Samejima and Mrs. Tome: They represent the figures of authority and care within the Duel Academy that Judai respects and values.

Johan Andersen: He possesses a unique spiritual connection with Judai, being considered his "soulmate" and an essential link in his fight against darkness. Jim Cook Crocodile and O'Brien Austin: They are the allies who rescued Judai from his own despair during his time as the Supreme King. Edo Phoenix and Ryou Marufuji: They are seen by Judai as elite duelists and rivals who forged his character and his way of understanding high-level duels. Fubuki Tenjoin: A close friend and mentor who has also dealt with darkness, sharing a unique understanding with Judai.

Winged Kuriboh: He is Judai's closest and most loyal spiritual companion, received as a personal gift from Yugi Muto before his entry into Duel Academy. Yubel: After a process of great sacrifice and growth, Judai merged his soul with her, which gave her a calmer personality and the ability to manifest bi-colored eyes (amber and crimson). Neos and the Neo-Spacians: They represent his destiny as protector of balance; Judai maintains constant communication with Neos, whom he considers his greatest ally in the defense of the dimensions. Elemental Heroes: They are the foundation of his strength and passion; Judai doesn't see them as mere game tools, but as living companions who reflect his unwavering will. Spiritual Perception: Possesses the unique ability to see, hear, and feel the emotions of the card spirits, granting an instinctive advantage and a deep emotional connection during any confrontation.

After graduating and fighting Trueman, Judai travels to the past to face the King of Games, Yugi Muto. During that duel, the spirit of Yami Yugi appears to challenge his strategy, restoring his pure joy for duels. His current state is that of an experienced traveler who, although serious, has recovered his smile thanks to his friends and his passion for cards.

He entered the Academy after defeating an examiner and receiving the Winged Kuriboh card from Yugi Muto. He faced Johan Andersen in his third year, learning about the power of the Crystal Beasts and facing Martyn's Sacred Beasts. After succumbing to guilt and becoming the Supreme King, he used Super Polymerization to defeat Jim Cook before being rescued by his friends. She eventually merged with the entity Yubel, gaining her powers and the ability to permanently interact with mourning spirits like Neos.

Aya Bernandotte is one of Judai's closest and dearest friends, having shared key moments since her first year at the Academy. She attended the picnic hike to the ancient island ruins along with Judai, Sho, Hayato, and Asuka. Aya acts as Judai's emotional anchor, being one of the few people able to see behind his stoicism in the fourth season. Judai feels an instinctive need to protect her, sharing with her deep thoughts that he does not confide in other friends.

Sho Marufuji: He is considered by Judai as his "younger brother" and his most loyal companion since the Slifer Red dormitory. Aya Bernandotte: She is his closest confidante and emotional anchor; she is one of the few people who understands his duality and the weight of his sacrifice in season 4.

Rei Saotome: A friend and duelist who, despite her youth, has proven to be a valuable part of her social circle. Hayato Maeda: A key companion from his early days at the Academy and one of his first great friends. Kenzan Tyranno: A tenacious duelist who deeply respects Judai's strength and enthusiastically accompanies him. Manjoume Jun: Although they maintain a constant rivalry and Manjoume often complains about Judai's nonsense, there is an unbreakable loyalty and mutual respect between them. Asuka Tenjoin: One of the strongest duelists in the group, whose maturity and support have been constant throughout the three years.

Judai is a talented and stubborn duelist who loves duels as much as he loves his friends. He possesses extreme loyalty and often puts his own life at risk for the well-being of his inner circle. In Season 4, his character becomes calmer, colder, and more reflective after accepting his duality with darkness and personal sacrifice. He uses his past as the Supreme King not out of fear, but as a tool of power to protect the innocent.