Kukumi Ureshino is a first-year high school student who serves as a close supporting friend to Nico Wakatsuki and Kara Minami. Before high school, she spent much of middle school feeling lonely, a period that ended when Kara invited her to a restaurant and the two became best friends. That connection draws her into the central social circle and helps her settle into a more confident school life.

By nature, Kukumi is quiet, gentle, and reserved around people she does not know well, yet she is deeply kind and willing to assist anyone who needs help. Her calm exterior conceals a passionate otaku heart. When the topic turns to anime and manga, especially her beloved in-universe series Uron Mirage, her shyness vanishes and she speaks with unrestrained excitement. This enthusiasm drives her to create fan art that attracts over ten thousand followers online, and she eventually co-founds a fan-work group called Fave Artist File with her teacher and fellow Uron Mirage admirer Yuri Makuwa.

As the story progresses, Kukumi’s hobby matures into a genuine ambition. She begins aiming for a career as a professional mangaka and ultimately achieves serialization in Weekly Shonen Jaguar with her own series Poof Poof Pwoof, Kemuri's Hazy Dayz. Her role in the narrative, then, is that of a supportive friend whose creative journey runs parallel to the main plot, demonstrating how a quiet, once-isolated person can cultivate meaningful relationships and transform a private passion into a published body of work. Her key relationships with Kara and Nico anchor her socially, while her collaboration with Yuri highlights a shared artistic language. Through these bonds and her own steady growth, Kukumi evolves from a shy girl drawing alone into a recognized creator with a loyal audience.