Matsuri Shibugaki is Naoki Kuzumi's cousin. After Naoki lost his parents and memory in an accident five years ago, Matsuri and her parents took him into their home. Though initially opposed to his arrival, Matsuri now lives with Naoki as part of the same household.

A first-year student at Hasumidai Academy while Naoki is in his second year, Matsuri often interacts energetically with him and their childhood friend Honami Fujieda during their commute.

She possesses blonde hair styled in waist-length twin tails and blue eyes, standing 155 cm tall with measurements of 77-56-79 cm and a B-cup bust size. Her birthday is July 17, making her a Cancer.

Matsuri exhibits an energetic, straightforward, and organized personality. Her hobbies include reading shoujo manga. She shares a particularly close bond with her classmate and best friend, Chihiro Tachibana.

Her typical attire includes school uniforms, sport bloomers, thigh-high stockings, and accessories like ribbons and headbands. She is also depicted wearing swimwear such as old-type school swimsuits and one-piece swimsuits.