The tomboyish, strongwilled daughter of the proprietors of a Shinto shrine, and a miko (shrine priestess) in her own right. Redhaired, pretty, and rather curvy, she is a master of exorcism. She has an aggressive shotacon tendence, an attraction to young boys, and Nino is often a target of this. Unusually enough for an anime series, while Mutsuki is not the main character or the de facto leader of the Holy Student Council, she is the strongest of the primary human characters and often acts like more like a leader than Haruto himself. She can use her prayer stick as a weapon, and frequently expels spirits out of Kazumi using her "Asahina Special" exorcism attack.