Aoi Takahashi is a second-year student at Tousei High School and a member of the Tesaguri Club, an unofficial group that brainstorms alternative activities for school clubs. Initially skeptical of club culture, she joined the club on a trial basis to confront her doubts. She is blunt and often critical of conventional club approaches, frequently dismissing them as annoying. Aoi has a pronounced self-consciousness about her physique, particularly envying others' bust size, which surfaces comically in group conversations. She is known for her intense focus on wordplay, regularly injecting brainstorming sessions with pun-based twists, such as weighting bicycles by playing on the word chari. She often teases fellow members, especially the youngest, Koharu Tanaka. In the second season, after the senior members graduate, Aoi and Koharu adopt an alternate timeline where the seniors never left, justifying this meta-narrative shift by citing in-universe inconsistencies. A flashback hints that she was less pun-obsessed before joining the club, suggesting personal growth through her involvement. Raised by her grandmother, her dialogue occasionally includes outdated cultural references. She channels her fear of heights into devising hypothetical scenarios for activities. Aoi appears in the third season spin-off, maintaining her personality while interacting with new characters.