Yūko Kumagai/Relationships

Rei Nasu
Nasu and Kumagai share a strong friendship and care deeply for one another, so much so that Nasu was outraged by Wen Sō disguised herself as Kumagai and, right before defeating the Neighbor, she claimed that she was taking revenge for the injuries she had inflicted on her friend. In combat Kumagai often serves as Nasu's bodyguard. Nasu calls Kumagai by her nickname followed by the diminutive suffix -chan, while the latter calls her by her first name, without honorifics.

Akane Hiura
Hiura was scouted by Kumagai, who is classmates with her brother. Kumagai is somewhat of a mentor figure to her and directs her in combat. As with the other members of the squad, however, their relationship also extends beyond that into friendship, with Kumagai being genuinely saddened at the prospect of Hiura leaving the team. Hiura addresses Kumagai by her surname followed by the honorific -senpai, while Kumagai uses her first name, without honorifics.

Sayoko Shiki
Kumagai is the one who scouted Shiki and brought her on as the squad's Operator. The two seem to be the most active while brainstorming the squad's strategies. They appear to be close, as Kumagai addresses Shiki by her first name, without honorifics.

Yūichi Jin
Jin has a history of catching Kumagai by surprise and smacking her backside without her consent, which she occasionally reacts to by punching him in the face and warning that she will report him if he keeps it up. However, she does not appear to genuinely resent him, as she immediately dropped the discussion when Jin advised her that the aces her squad would be up against in the next match were currently sparring in a solo rank battle. He addresses her by her nickname followed by the suffix -chan, while she uses his surname and appends the honorific -san.

Kei Tachikawa
Tachikawa calls Kumagai by her nickname "Kuma," without honorifics. He does so because, in spite of having been corrected by her six times in a row in the past, he is unable to read the characters in her surname, and Kumagai has come to accept it. In his commentary of Nasu Squad's match against Tamakoma Second and Suzunari First Tachikawa bluntly stated that feelings hardly impact the outcome of a battle when Kaho Mikami praised Kumagai's resolve, but he later pointed out that thinking the opposite would equate to holding that the loser did not want the victory enough, implying that it would be a disservice to Kumagai, whereas he was actually quite impressed by her passion.

Kuniharu Kakizaki and Ryō Utagawa
Kakizaki, Kumagai, and Utagawa play basketball together in their free time.