Mizore Amatsuka, the 17-year-old second daughter of the Amatsuka family, possesses black hair cut to ear length and black eyes, standing 164cm tall. She attends high school as a third-year student. Exhibiting a level-headed demeanor, Mizore frequently engages in teasing behavior toward her siblings. She expresses a specific interest in Yotaro Amatsuka, the brother joining their family, declaring she would not mind having him as her partner. One of nineteen sisters, Mizore observes and comments on the relationships developing between Yotaro and her other sisters. During a river outing and subsequent hot springs trip, she witnesses Tsurara (the sixth daughter) sharing a kiss with Yotaro. Following this event, Mizore also kisses Yotaro herself. Later, she teases Tsurara about the incident. Mizore further participates in a family promotional video, which includes filming in swimsuits at a river location; her swimsuit appearance is included among her cataloged traits.