Kumin is a second-year high school student who transfers into the same school as Rikka and Yuuta. She becomes part of Rikka’s club after being drawn in by their odd activities and the promise of a place where she can nap freely. Though she does not suffer from “chūnibyō” herself, she accepts and supports the other club members with warmth and patience.

She takes pride in her unique club title and sees napping as both a hobby and a skill, often encouraging others to try it. Kumin quickly becomes an integral member of the group, providing emotional balance and often helping to mediate conflicts.

Kumin has shoulder-length brown hair with a fringe that sweeps to the side, and large, soft brown eyes. She is typically seen wearing the standard school uniform, though she often carries a pillow or blanket with her, symbolizing her constant desire for a comfortable nap.

Her facial expressions are gentle and sleepy, and her posture is often relaxed or slightly slouched emphasizing her laid-back attitude. She exudes an aura of calm that contrasts with the energetic and eccentric behavior of her clubmates.

Kumin is gentle, serene, and nurturing, with a passion for afternoon naps that borders on philosophical. She is rarely angry, and even in chaotic situations, she maintains a peaceful and optimistic outlook. Despite her sleepy tendencies, Kumin is surprisingly sharp and observant, often catching on to emotional undercurrents that others miss.

She doesn’t share in the delusions of chūnibyō but respects the imaginative world her friends live in. Her calm demeanor and affectionate personality make her well-loved by her peers, and she serves as the emotional support of the group, even if she prefers to do so while lying down.