Volley-bu-chan, also called Volleyball-chan, recurs throughout the series as captain of the high school volleyball team Ai-chan attends, sharing a close friendship with her. She possesses a tall frame, a tomboyish haircut, and notably large breasts consistent with other female characters; her school uniform or athletic wear like tracksuits and volleyball outfits form her typical attire. Her breast size, initially speculated as G-cup, was confirmed as F-cup in Chapter 97.

Outgoing and energetic, she ranks among the school's most popular students and fiercely protects Ai-chan. This protectiveness includes defending Ai-chan against female peers who initially resented her for male attention and appearance, with Volley-bu-chan eventually improving Ai-chan's social standing.

Her interactions with Ai-chan feature frequent teasing, often targeting Ai-chan's breasts through groping that causes annoyance. This behavior stems from her explicit sexual attraction to Ai-chan, marking her as a prominent queer-coded character without explicit sexuality labels.

Her background connects her to the Salaryman (her uncle, who interacts with Ai-chan on trains) and a brother (one of few male characters depicted with visible eyes), linking school and adult dynamics. Her role evolves beyond comic relief, maintaining breast-focused humor while her protective influence highlights her importance to Ai-chan and the school environment.

Trivia notes her August 24th birthday, blood type B, and volleyball expertise. Official Q&As cite madder as her favorite color, fillet meat as preferred food, gaming as her ideal day-off activity, and running for stress relief. She claims proficiency in volleyball and no significant academic weaknesses.

She appears in the original webcomic, manga, and both anime seasons plus OVAs: Season 1 (episodes 2, 5, 7, 10, OVA) and Season 2 (episodes 1, 7, 11, 12, OVA).