Hibiki Kimiya is a first-year Mitoya High School transfer student with pale skin, light-blue hair, and green-blue eyes. He constantly carries a scyhe and wears a distinct outfit: a white dress shirt fastened with a black ribbon, a black and red cape, and black pants featuring folded suspenders. High-heeled boots compensate for his short stature.

Characterized by shyness and eccentricity, Hibiki habitually blames his own bad luck for negative events. He adopts a self-styled "god of death" persona, hoping this guise will earn him greater trust, particularly from Kabuto Hanadori—a deeply admired figure Hibiki views as similarly unconventional. Believing emulation of Kabuto will lessen his concern for others' opinions, Hibiki transferred specifically to SanDaoShi High to befriend him, seeking connection with a perceived kindred spirit.

Hibiki's attempts to interact with Kabuto are typically met with indifference or dismissal, reinforcing his retreat into a self-deprecating worldview. His background includes persistent social isolation, and he struggles to assert himself within groups. Maintaining a quiet presence, he frequently internalizes anxieties and misfortunes.