Kurumi Nukui

Kurumi Nukui is the younger sister of the story's main character, Hibiki Nukui. As a fifth-grader serving as class president, she projects a sharp and no-nonsense attitude—especially toward her stay-at-home brother, whom she scolds relentlessly. Beneath that prickly exterior, however, lies a deeply devoted sibling who quietly handles most of the household chores and worries about him more than she lets on. Her exceptional piano skills earned her a spot as the keyboard player in the band Dragon≒Nuts. Whenever Hibiki grows close to other young girls, Kurumi's fierce possessiveness becomes impossible to hide.