Kotori Minami, a second-year student at Otonokizaka High School, stands as a central pillar of the school idol group μ's, maintaining a lifelong bond with childhood friends Honoka Kosaka and Umi Sonoda. Their trio, rooted in shared experiences since kindergarten, forms the emotional foundation of the group’s dynamic. Her mother’s role as school director occasionally intertwines with μ's activities, adding familial ties to their institutional context.

Known for her gentle, empathetic nature, Kotori balances compassion with a habit of hesitating in decisions, often subordinating her desires to preserve group harmony. Beneath her modest, occasionally absentminded demeanor lies a sharp intellect, reflected in her academic honors and hands-on talent for fashion design. Collaborating with Nico Yazawa, she crafts costumes that harmonize individual member identities with cohesive visual themes, merging creativity with technical precision.

Her dual identity as "Minalinsky," a celebrated maid at an Akihabara café, underscores her versatility. This secret persona exemplifies her calm professionalism and adaptability, traits mirrored in her meticulous choreography planning and logistical coordination for μ's. Physical agility—such as folding her legs behind her shoulders—complements her methodical work ethic.

A pivotal internal conflict arises when Kotori contemplates studying fashion abroad, torn between loyalty to μ's and personal ambition. This dilemma catalyzes her evolution from relying on others’ expectations to confronting her aspirations, though she postpones her departure to stay with the group until its eventual disbandment.

The film expands her role as she orchestrates a national school idol festival, channeling her organizational acumen to cement μ's legacy. During the group’s dissolution, she navigates emotional challenges, offering steadfast support to Honoka and Umi through farewell performances.

Supplemental materials depict her structured daily life, balancing academics, quilting, yoga, and time with friends. Personal quirks—a fondness for cheesecake, avoidance of garlic, and a wardrobe favoring soft whites and grays—enhance her approachable, nurturing image.

Kotori’s narrative arc, though subtle against ensemble-driven plots, traces incremental growth in self-assurance and agency. Her journey reflects the series’ emphasis on communal bonds and individual maturation, positioning her as a stabilizing force whose quiet determination bolsters both μ's and her own evolving identity.