Yūma Kuga/Relationships

Yūgo Kuga
Yūgo is Yūma's father. Yugo tries to keep Yūma out of danger by discouraging his participation in serious battles, but Yūma does not take him seriously. As a father, Yūgo took time to teach Yūma life lessons. He loved Yūma deeply and died to save him, passing on his side effect and black trigger. Yūma wishes to bring his father back to life. He is baffled by why Yūgo sacrificed himself for a son who got himself killed because of his own disobedience.

Replica
Replica is Yūma Kuga's guardian and a recurring supporting character. It is a self-described "multi-task Trion Soldier" created by Yūma's father. Yūma seems to enjoy Replica's companionship and respects his opinion and becomes devastated when Replica is deactivated and taken away to Aftokrator.

Osamu Mikumo
Yūma and Osamu share a mutual respect for one another. Yūma admires Osamu for his honesty, sense of duty, and eagerness to help others at his own cost. Osamu looks up to Yūma for his fighting experience and strength and wants to give Yūma a reason to keep living. Yūma is considerate of Osamu's position in Border. He tries to advance Osamu within the organization's ranks and decides to take on the task of taking Osamu and Chika to A-rank.

Chika Amatori
Yūma is impressed by Chika's abundance of trion. Just like Osamu, Yūma is affectionate towards Chika and strives to make sure she is safe.

Yūichi Jin
Yūma respectfully acknowledges Jin's strength, admitting that he might lose to Jin in a fight. However, he trusts that Jin would not become his enemy. Jin looks out for Yūma, directly facing off against HQ multiple times to stand up for him. When HQ sends the Expedition Force for Yūma, Jin refers to him as his "cute junior" and proceeds to fight for him.

Kirie Konami
Konami singled Yūma out as the strongest of the Osamu-Chika-Yūma team and agreed to help train the team only if she got Yūma. She was looking down on Yūma as "midget" while demanding his respect, that quickly changes when Yūma defeates her during training. They form a mild rivalry during training, and both see the other as a worthy opponent. Konami seems competitively proud of her trainee, proclaiming Yūma's potential to the team when Chika was considered the best candidate first. She also cares for him deeply.

Shiori Usami
Shiori seems to care for Yuma.

Shun Midorikawa
After Midorikawa defeated Osamu in Battle, Yūma stepped in, they quickly become friendly rivals afterward. Midorikawa is also one of the few people to refer to Yūma by his given name instead of his surname.

Kō Murakami
Yūma seems to have a good relationship with Murakami, as they are seen having mock battles since their first battle, most of which ends with Murakami's victory, usually winning by 2 points every time they fight. Because of his Side Effect, and Murakami being the #4 Attacker in Border, Yūma seems to respect him.

Masato Kageura
Yūma and Kageura seem to have a good relationship, despite their rocky start. During their match, they assist each other in defeating Sumiharu Inukai and Shinnosuke Tsuji to save Chika, despite being on different teams, and they later schedule a ranked match, although it doesn't take place as Yūma gets lost on the way there, and is eventually "summoned" by Mikumo. Murakami stated that Yūma would appreciate Kageura's honest nature, and would be compatible with him.

Nozomi Kako
Under her position in Border, Yūma seems to respect Kako, somewhat knowing of her skills. She wanted to recruit Yūma to her unit due to his skills, and to his surname starting with a "K," as she wants to form a team of pros with surnames starting with K. She even jokingly considered "recruiting him by force," to which Yūma said he'd fight back.