Hibiki, whose name means "sound" or "echo," attends class with Reika Tosu. She currently works at a high-class cabaret club in Chiba, having transitioned from a previous cabaret job after Nobuto Matori assisted her in securing the position. Hibiki met Nobuto about a year before the story's events and became his girlfriend. Despite his infidelity, she maintains single-minded devotion to him and forgives his cheating. She possesses knowledge of a significant secret tied to Nobuto, information unknown even to the criminal organization he is associated with.