Sumire Misaki carries the weight of a prestigious artistic legacy: her mother is a world-renowned flutist performing with top orchestras, while her father and older sister are highly accomplished visual artists. This heritage generates intense pressure and anxiety about meeting expectations. Her fear of failure focuses sharply on singing, rooted in a past incident where she made a noticeable mistake during a choir performance attended by her family. This lasting embarrassment drives her to avoid public singing and frequently skip choir rehearsals, despite possessing genuine talent as a soprano. She practices secretly behind Nadeshiko Academy's main building and often listens to other choir members during lessons.

Socially, she maintains a reserved and emotionally restrained exterior, appearing shy and easily intimidated, which hinders her ability to form friendships. This contrasts with a hidden aspect of her personality: notable proficiency in arcade games, which she uses for stress relief, defeating opponents with ease during visits to game centers. An additional challenge is her significant fear of heights. Her character development involves forming a meaningful friendship with Elis Hōsen after Elis assists her in addressing performance anxiety. This connection provides crucial emotional support, helping her gradually build confidence. Her journey centers on managing familial pressures and personal insecurities through these interpersonal connections and coping strategies.