Hayase Nagatoro is a petite, athletic high school girl with long straight black hair pinned back by white clips, sun-kissed tanned skin, large expressive amber-maroon eyes, and a signature cocky, sadistic grin that often reveals her prominent canines. Beneath her energetic, sarcastic, and relentlessly teasing exterior—where she constantly bullies and plays with her "Senpai"—lies a deeply affectionate, surprisingly shy, and fiercely protective person whose teasing acts as a mask for her genuine romantic feelings.