Tsumugi Aoba, a third-year Yumenosaki Academy student and Switch member, grew up assuming a protective older brother role at his parents’ dance and idol school. Among the children he shielded was Natsume Sakasaki, whose family received free lessons as a gesture of gratitude. A childhood promise to Natsume binds him to never cut his hair—a vow he maintains until fulfilling its unspecified terms. As second-year class president, he joined the unit fine under Eichi Tenshouin, leveraging his social network to advance the group’s goals. His detached demeanor masked a willingness to protect fine’s interests, even orchestrating the burning of school records. These actions during the "War" era strained his bond with Natsume, who blamed him for dismantling the cherished "five oddballs" group. Post-fine, he co-founded Switch with Natsume and Sora Harukawa, designing their unit outfits to reflect their intricate dynamics. Though outwardly gentle and prone to anxiety, he reveals a sharper edge in clashes with Natsume and Shu Itsuki during incidents like *Fortune Banquet* and *Magical Halloween*. His fascination with divination manifests in daily rituals involving fortune-telling-inspired lucky charms and feng shui practices. Haunted by War-era guilt, he often works late into the night, his diaries hinting at unresolved struggles with self-worth and reflections on Eichi Tenshouin. Peer support gradually steers him toward reconciliation with his past. By *Wonder Game*, he plans to join NEW DIMENSION agency post-graduation while remaining in Switch, signaling newfound stability. His social adeptness and warmth mask deep-seated fears of disappointing others, most starkly visible in his fraught dynamic with Natsume. Beneath their resentful, passive-aggressive exchanges lies unspoken mutual care—a fragile thread connecting their shared history and lingering tensions.