Kotori Minami is a second-year student at Otonokizaka High School and one of the founding members of the school idol group μ's. She has a gentle and soft-spoken demeanor, often seen with a calm, warm smile. Kotori is known for her kind-hearted and supportive nature, frequently acting as a mediator and emotional anchor within the group. Despite her shy and easily flustered appearance, she possesses a surprisingly strong will and a keen eye for detail, especially in matters of design and aesthetics.

Kotori’s primary motivation stems from her deep care for her friends, particularly Honoka Kōsaka and Umi Sonoda, with whom she has been close since childhood. When Honoka proposes forming a school idol group to save their school from closure, Kotori eagerly supports her, not out of a desire for fame or competition, but to help Honoka achieve her dream and to preserve their shared memories at Otonokizaka. Over time, Kotori develops her own sense of pride in μ’s and a personal goal to express herself creatively through costume and stage design.

In the story, Kotori serves as the group’s chief costume designer, creating all of μ’s performance outfits. Her artistic talent is a notable ability, as she can quickly sketch and sew elaborate costumes that reflect each member’s personality and the theme of their songs. She also contributes to choreography discussions and often helps resolve conflicts with her diplomatic, peacekeeping nature. Her role is less about being the loudest leader and more about quietly holding the group together through loyalty and practical support.

Key relationships define much of Kotori’s character arc. With Honoka, she shares an unbreakable bond of trust, often indulging Honoka’s reckless enthusiasm while gently reining her in when necessary. With Umi, who is more strict and disciplined, Kotori acts as a bridge between Honoka’s spontaneity and Umi’s rigidity. The three form a core triangle of friendship that anchors μ’s. Kotori also interacts warmly with other members: she admires Eli Ayase’s leadership, consoles Rin Hoshizora’s insecurities, and shares a quiet camaraderie with Hanayo Koizumi, another soft-spoken member. Later, she grows close to Maki Nishikino, often praising Maki’s musical compositions.

Kotori undergoes notable development as the series progresses. Initially portrayed as somewhat passive and prone to following Honoka’s lead, she gradually finds her own voice. A key turning point occurs when she receives an unexpected opportunity to study fashion design abroad, forcing her to choose between her personal ambition and her commitment to μ’s. This conflict reveals her inner strength: she ultimately decides to stay with the group, not from dependence, but from a clear-eyed choice that being with her friends and seeing μ’s succeed is what she truly wants. The experience matures her, and she becomes more assertive in expressing her own ideas, both in costume design and in group decisions.

Notable abilities beyond costume design include her sewing speed and precision, as well as a natural grace in dance. While not the most powerful singer or dancer in μ’s, her movements are fluid and elegant, complementing the group’s overall harmony. She also possesses surprising physical endurance and a subtle strategic mind, often suggesting practical solutions to logistical problems—such as managing rehearsal schedules or sourcing materials on a limited budget. Her kindness is itself an ability in the context of the group, as she consistently diffuses tension and encourages others without judgment.