Aoi Ogiyama, childhood friend and same-year classmate of Subaru Hasegawa, stands 163 cm tall with a January 9 birthday (Capricorn) and inconsistently documented blood type of either A or O. Her indigo hair flows in a long ponytail, complementing violet eyes and a moderately developed figure. Previously a center for Kirihara Middle School’s girls' basketball team, she later managed her high school team.

Harboring unreciprocated romantic feelings for Subaru, she struggles with jealousy toward girls close to him. Her personality blends righteousness with harshness, notably when confronting perceived improprieties. She once violently accused Subaru of lolicon activity after misunderstanding his coaching of elementary schoolgirls, challenging them to a high-stakes basketball match to test their dedication. This confrontation led to reconciliation, with Aoi joining as assistant coach.

Her role evolved from opposing Subaru’s involvement to supporting the team. She coached the fifth-grade Keishin Girls Mini Basketball Team before its merger, solidifying her position as Subaru’s assistant coach. Her abilities include fundamental basketball skills from playing experience. She channels concern for Subaru’s well-being and academic struggles into coaching support. Initial rigidity softens through team interactions, though vigilance against perceived misconduct remains.

Her surname Ogiyama combines "reed/rush" (荻) and "mountain" (山). The name Aoi may mean "hollyhock" (葵), "blue" (青い), or "cyan" (蒼い) depending on kanji usage.