Kasumi Horiguchi, a classmate and close friend of the protagonist, serves as a constant presence in school-related scenarios and casual social exchanges. Oblivious to the protagonist’s secret marriage, she regularly teases or remarks on their behavior around romantic interests, amplifying comedic tension through her uninformed assumptions.

Her interactions frequently spark humorous chaos, exemplified by incidents like seizing a misplaced love letter meant for the protagonist and announcing its contents publicly. Such antics precipitate awkward situations, inadvertently spotlighting the protagonist’s concealed emotions and exacerbating their struggle to keep their marital status hidden.

With a bubbly and mischievous demeanor, Kasumi eagerly steers conversations toward romance and relationships, her playful curiosity often setting up scenarios ripe for misunderstandings. She frequently joins the protagonist in club events and cultural festivals, though her participation typically serves as comedic relief rather than driving substantive plot developments.

Her backstory and personal history remain unexplored across official materials, with her narrative purpose firmly anchored in generating lighthearted tension through humorous misinterpretations of the protagonist’s actions. She maintains a steady role as a secondary figure, catalyzing episodic challenges tied to the protagonist’s juggling of public and private lives.