Haru is a devil who resides in the Magic World, having originally lived there as a sorcerer before undergoing a transformation into her current divine form. Her physical appearance is notable for her black hair, black eyes, and large wings that are characteristic of her kind, as well as bangs that frame her face, and she stands at approximately 172 centimeters tall. As a devil, Haru exhibits a personality that is generally carefree, aloof, and apathetic, with a tendency to prioritize her own needs and interests over those of others. Despite this detached demeanor, she does show empathy and a more caring side in her interactions with her husband, Professor Kasukabe, demonstrating a specific capacity for affection within her closest relationships.

Her primary personal motivation is her love for music, with a particular passion for singing, which she practices frequently as part of a band that includes other devils and the powerful devil Chidaruma. This musical pursuit appears to be a central aspect of her identity and daily life. In the story, Haru plays a role as a devil who is unusually friendly with a human, a behavior that is considered strange enough to be remarked upon by other characters, indicating a unique disposition for a being of her status. Her key relationships are primarily defined by her marriage to Professor Kasukabe, to whom she is deeply connected, and her musical collaborations with her fellow band members in the devil's music group. Currently, there is no direct information about her development throughout the narrative or any specific notable abilities beyond those generally associated with devils and her proficiency as a singer.