Aoi Ogiyama, sharing Subaru Hasegawa's high school and year, is his childhood friend and former basketball teammate. Standing 163 cm tall with violet hair and grey eyes, she possesses a moderately athletic build. Her versatile skills as a center and power forward significantly contributed to Kirihara Middle School's girls' basketball success.

She nurtures unspoken romantic feelings for Subaru, often becoming flustered or defensive when emotions surface. This manifests as protectiveness and flashes of jealousy when other girls interact with him. Deeply concerned for his well-being, especially after his high school basketball club's suspension, she fears he might abandon the sport entirely. To prevent this, she organizes basketball sessions with mutual friends.

Initially misunderstanding his intentions, she fiercely opposes Subaru coaching an elementary girls' basketball team, fearing misconduct. She confronts him and demands he stop. However, witnessing the girls' dedication and resolving the conflict through a basketball match leads to reconciliation. She then becomes assistant coach for the Keishin Academy girls' team, briefly coaches the fifth-grade team, and ultimately returns to assist Subaru full-time.

Her personality blends assertiveness and compassion. Principled and quick to react against perceived misconduct, she sometimes emphasizes disapproval physically, like kicking Subaru. Yet she is fundamentally caring, offering Subaru academic support and diligently guiding younger players. As a coach, she willingly shares basketball knowledge and demonstrates tactical understanding. Her adaptable playing style excels in forward positions.