Mizuki is the empress of the River Guard, a group specialized in water-based abilities and katana swordsmanship. Like all other members, Mizuki is an expert swordswoman. She is strict, cold, and smug. She will defend her title as empress of the River Guard no matter the circumstances. Mizuki is also extremely protective over her brother, Stray, and he is the only one she’s ever showed her true emotions to.