She is a first year in high school like her illumination STARS unit members Mano Sakuragi and Meguru Hachimiya. Initially, Hiori was unsure about being part of illumination STARS. She worries that she isn't as skilled as her new unit mates, Mano and Meguru. Mano has a naturally pretty singing voice and Meguru has played sports for a long time, helping her with her stamina and dance. Hiori worries that she's holding the unit back, despite working just as hard as the other two girls.