Kazuma Hiyama masks deeper complexities beneath his delinquent facade, cloaking genuine feelings with impulsive pranks and sharp remarks. Leading a group in teasing classmates—especially Yui Aoi—his behavior roots back to a childhood incident: witnessing Yui’s tears during a Mother’s Day event after her mother’s absence, followed by Marin Ogura’s warning against mentioning the topic. Agitated by Yui’s subsequent forced smiles, he lashed out, demanding she drop the pretense, yet concealed a buried tenderness beneath his abrasive exterior.

A turning point arrives when he aids Yui in recovering her mother’s necklace, catalyzing mutual honesty and a fledgling romance. This act softens his rough edges, revealing a protective, earnest side, though he stumbles in navigating Yui’s emotions—evident in clashes over her bond with Inaba Mikami, a rival from cram school.

Kazuma’s undefined family history, marked by an absent mother, contrasts with his name’s symbolism: “Hiyama” merges *hinoki* (cypress) and “mountain,” reflecting steadfast resilience, while “Kazuma” (“one” and “soar”) hints at untapped aspiration. His chalky brown hair, dark purple eyes, and Rabbit Panda-adorned outfits mirror a blend of playful mischief and guarded vulnerability. Evolving from class clown to devoted partner, his journey weaves adolescent trials—jealousy, miscommunication, seeking familial acceptance—with gradual maturity, balancing comedic defiance and quiet emotional growth.