Yūya Sakaki (manga)/Relationship

Yūshō Sakaki
Yūshō is Yūya's father. Although their interaction has not been shown much, it was clear that both loved and believed in each other like a father and son would. Not only Yūshō sent Yūya to the past to save his life, he also entrusted Yūya with a mission to find the creator of G.O.D even though Yūya didn't know much of the detail, believing that his son will succeed his last wish. Yūya, in return, was actually unwilling to left his father when World Illusion began, crying right before he was sent to the past. Trusting his father, Yūya determined to carry out the duty his father left to him, showing how much he respect and love his father.

Yūto, Yūri, and Yūgo
Yūto, Yūri, and Yūgo are Yūya's older brothers. Since they were children, the four brothers have a deep and close relationship to the point they are willing to sacrifice their own lives if it's necessary. Their different personalities sometimes makes them clash with each other, but this is usually done out of concern for each other's well-being. Yūya cares a lot for his older brothers. He is protective of them, risking his life to save them whenever they are in danger. Even after he lost his memories about them, they quickly grew close like they once were. Yūto, Yūri, and Yūgo were also protective of their younger brother, even more than Yūya does to them. Out of the four brothers, the three older brothers seemed to love Yūya the most to the point they formed a brotherly rivalry against each other for Yūya's affection. One of such rivalry is when they were competing who can get the youngest brother's attention the most during the youngest's birthday. The three older brothers always placed Yūya above themselves, choosing to save him at the cost of their own lives without a slightest bit of hesitation when only one of them could be saved during G.O.D's rampage. Even after becoming one with Yūya, they continue to watch over him in his quest to find G.O.D, going as far as erasing Yūya's memories about them being brothers as to not make him sad of their deaths even though they were precious memories for them. Despite the protectiveness, this doesn't stop them from trusting each other's skills to fight against the enemies and sometimes work together, displaying excellent teamwork.

Yuzu Hīragi
Yuzu is Yūya's manager and later revealed to be his future mother. The two has a rather unusual start; Yuzu wants Yūya to teach at her Duel school so she tricked him into signing the contract and forcefully make him to accept her as his manager, much to Yūya's own dismay. As in the beginning Yuya lost part of his memories, he didn't recognize Yuzu as his future mother, but their kind and friendly nature allows them to quickly get along quite well. Yūya would protect and save Yuzu when she is in danger, and Yuzu will assist Yūya in his quest regardless of the danger and shows genuine concern when he is injured. Like Yūto, Yuzu also scolds Yūya when she thinks he is being overly optimistic, but unfortunately, she usually has no choice but to go along with him. Despite being unaware of their blood relation, Yuzu grew to care so much for Yuya and wishes to know him more, no longer caring even if he doesn't teach at her school and is saddened when they must part ways.

Reiji Akaba
Due to the history between their fathers, both are quickly not on good terms with each other the moment they met. While Reiji admitted that he doesn't hold any grudge against Yūya, Reiji sees Yūya as a threat that will destroy the world due to his belief that Yūya is planning to control G.O.D's power and is determined to capture him at all cost. The fact that Yūya is the son of Yūshō whom he deemed responsible for his father's death also resulted with Reiji got offended when Yūya introduced Reiji as his friend. Yūya understand Reiji's hatred for his father, and sadly accepted the fact that they have to clash against each other, though Yūya believes the day will come when Reiji will finally understand the truth. Even after Reiji learned that Yūya's goal was to destroy G.O.D, Reiji was still reluctant to accept him as ally.