Mahiru Tsuyuzaki is a second-year student in Seisho Music Academy's 99th Graduating Class Actor Training Department. Hailing from a Hokkaido farming family and a graduate of Kitachian Junior High School, her passion for performing arts was ignited by her grandmother, who introduced her to singing, baton twirling, and stage plays, ultimately encouraging her Seisho application. Despite notable pre-Seisho achievements including third place in the 2016 Japan Baton Championship U-15 Solo Twirl and runner-up in the 2016 National Junior High Baton Twirling Competition, alongside training in choir, piano, classical ballet, and modern dance, she initially struggled with self-confidence upon enrollment, feeling overshadowed by her peers' talent.
Mahiru often downplays her own abilities and seeks validation through supporting others, particularly her roommate Karen Aijo, whose cheerful and outgoing nature she admires. She finds purpose in managing Karen's daily needs and shared responsibilities. This dynamic is disrupted when Hikari Kagura, Karen's childhood friend, transfers to Seisho. Mahiru experiences intense jealousy and insecurity, fearing Karen no longer needs her. Her explicitly acknowledged romantic feelings for Karen manifest in actions like seeking indirect kisses and viewing Hikari as a rival, contributing to emotional turmoil culminating in the Revue of Jealousy, where she confronts Karen about being replaced.
Her development focuses on overcoming these insecurities. After losing to Karen in the revue, she begins recognizing her own worth independently of others' validation and rediscovers her initial motivation for attending Seisho: to shine confidently on stage like the actresses who inspired her. This growth allows her to reconcile with Hikari and eventually support both Karen and Hikari as someone they rely on, such as helping search for Hikari when she disappears.
Mahiru's revue performances reflect her journey. Early introductions emphasize devotion to others, like "I adore the shining stage, but... I love it even more when you shine." Later iterations, particularly in the mobile game *Re LIVE*, shift toward self-affirmation: "I love the brilliant stage, so I will believe in my brilliant self and walk on." Her revue outfit features a green military-style jacket and a mace weapon symbolizing her baton-twirling prowess, sometimes wielded like a baseball bat reflecting her love for the sport. In the film *Revue Starlight: Rondo Rondo Rondo*, her resolve solidifies further; her introduction includes: "I will sing the joys of standing on stage / And dance my resolve to stand on stage. / I swear to continue acting / with strength, lovingly, and beautifully," underscoring her commitment and acceptance of her unique brilliance.
Characterized by warmth, kindness, and quiet determination, Mahiru excels at domestic tasks and often shares produce from her family's farm with classmates. She dislikes the card game Old Maid and sad stories, while her favorite food is potatoes. She is the only character in the franchise whose romantic feelings for another girl are explicitly confirmed, adding depth to her interactions. Her journey concludes with a matured perspective: supporting Karen and Hikari's bond while embracing her own indispensable role within the group.