Nanase Tsukumo

Acting as the homeroom teacher for Yuuta and Rikka, this instructor balances a gentle demeanor with a mischievous, slightly sadistic streak. She takes great pleasure in teasing her students, often targeting Rikka with playful jabs. While she maintains a professional role at the school, her close bond with the protagonists allows them to call her by the affectionate nickname Nana-chan, highlighting the warm, familiar connection they share outside of the classroom.