She is a shy and timid girl who often has troubles speaking for herself. She is easily subject to bullying, and is often defenseless. However, when the sun sets, Mahiru's alternate personality, Shinya Banba, appears. Shin'ya is the complete opposite of Mahiru, and refers to herself (or even himself) as "ore (俺)", which is a rather rough masculine way when referring to oneself. Shinya has an aggressive and borderline insane appearance.