Inui is the caretaker of the student dormitory for Naginomori Gakuen. He takes a special interest in the main student cast of -trinity soul-, even to the point of almost inviting himself to be the driver for an overnight trip they intended to take. During the trip, it becomes apparent he has a deeper interest in the Personas the cast can use, secretly recording the events of Yumi Tasaka's rescue. Despite being the dorm's caretaker, he does secretly keep an old dog against the dormitory's rules.