Hotaru is a fifth grade elementary school student who transfers into the Asahigaoka Branch School from Tokyo. Tall and quite developed for her age, she doesn’t look like an elementary school student and is thus often treated like an adult. She admits to be not good at exercise but is shown to be stronger than Natsumi. She usually maintains a calm and composed appearance but also has a childish side and freaks out easily.
She admires Komari to the point of harboring a crush on her bordering on obsession. She had crafted mass amounts of Komari-like dolls which she tried to keep secret.