Rui Ijigawa is a sharp-witted, mischievous troublemaker and Iyona Kawai’s closest confidant. Her interactions with Honmaru Edojo revolve around relentless bullying—verbal barbs, physical pranks, and targeted harassment—rooted in childhood rejection, which fuels lingering resentment and unresolved emotions. Beneath her antagonism simmers overt romantic interest, generating a complicated dynamic of mockery and concealed longing.

Though her teasing borders on aggressive, flashes of vulnerability or veiled concern occasionally pierce her abrasive facade. She joins Iyona in group activities and school events, wielding a biting wit that starkly contrasts her friend’s gentler nature. Her rapport with Taruruto fluctuates between fleeting curiosity and casual teasing, though she largely regards him as a background player.

Rui’s appearance features blue hair styled in a sharp bob cut accented by a hair bow, paired with piercing blue eyes. Her practical, slightly tomboyish wardrobe favors pants and simple tops. As the narrative unfolds, her role transitions from primary antagonist to a layered presence within the group, with subtle shifts toward softer behavior emerging over time. Her evolution remains anchored to her fraught bond with Honmaru and the core cast, preserving her signature blend of cunning antics and hidden emotional depth.