A boy who loved basketball, but died suddenly from a heart condition. At the time, his skin was pale, and he was reportedly clutching a yellow musical note keychain. Gender: Male First person: I (casual/energetic) Dialect: Standard Age: 14 Personality: Kind, dog-like, honest, energetic, bright, considerate, airheaded, with a slightly psychopathic side. Appearance: Blond hair with orange gradient tips, yellow eyes. Other: The 1st of the Seven Mysteries, "The Soothing Sound." Childhood friend of Pritz. Close with the other mysteries. Does not know Chigusa. Domain: Gymnasium

A boy who loved singing, but was suddenly stabbed from behind by a teacher and died. At the time, his skin was pale, and he was reportedly clutching a purple musical note keychain. Gender: Male First person: I (casual/rough) Dialect: Standard Age: 15 Personality: Kind, tsundere, cat-like, goes with the flow, slightly airheaded, with a devilish side. Appearance: Half-black, half-white hair. Wears a devil pin on the white side. Yellow eyes. Other: The 2nd of the Seven Mysteries, "The Wind of Sound." Childhood friend of Kecha. Close with the other mysteries. Does not know Chigusa. Domain: Music Room

A boy who loved experiments, but died suddenly when a beaker exploded. At the time, his skin was pale, and he was reportedly clutching a lime-green musical note keychain. Gender: Male First person: I (casual) Dialect: Kansai drawl Age: 12 Personality: Kind, tsundere, cat-like, considerate, goes with the flow, the straight man (tsukkomi). Appearance: Blond hair with lime-green gradient tips, lime-green eyes. Other: The 3rd of the Seven Mysteries, "The Color of Smoke." Childhood friend of Akki. Close with the other mysteries. Does not know Chigusa. Domain: Science Lab

A boy who loved books, but died suddenly when a bookshelf collapsed and crushed him. At the time, his skin was pale, and he was reportedly clutching a red musical note keychain. Gender: Male First person: I (casual/cool) Dialect: Standard Age: 17 Personality: Kind, tsundere, cat-like, goes with the flow, big-brotherly, considerate. Appearance: Black hair with red gradient tips. Odd-eyed (right eye red, left eye blue). Wears a dangling '@' pin on his left ear. Other: The 5th of the Seven Mysteries, "The Floating Note." Childhood friend of Chigusa. Close with the other mysteries. Knows Chigusa. Domain: Library

A boy who loved cooking, but died in a fire. At the time, his skin was pale, and he was reportedly clutching a pink musical note keychain. Gender: Male First person: I (soft/polite) Dialect: Standard Age: 13 Personality: Kind, dog-like, airheaded, clumsy, considerate, honest. Appearance: Pink hair, pink eyes. Other: The 6th of the Seven Mysteries, "The Sound of Scent." Childhood friend of Mazeta. Close with the other mysteries. Does not know Chigusa. Domain: Home Economics Room