Harumi Kumashiro is a supporting character and member of the organization Grand Paladin. She attends school with her childhood friend, Miu Inaba, maintaining their long-standing close bond. Outside Grand Paladin, Harumi works as an office worker.

Her personality blends protective instincts, especially concerning Miu's well-being, with a desire to be pampered by Miu. This includes aspirations to avenge Miu against perceived threats. Physically, Harumi has light brown hair, orange eyes, and a shoulder-length hairstyle, coupled with notable judo proficiency.

In Grand Paladin's combat operations, Harumi pilots a mechanized bear unit, consistent with the group's animal motif. Utilizing psychic abilities, she manifests gigantic lightning attacks during significant battles. These psychic powers become potent enough to trigger physical transformations into a bear-like creature during intense combat.

Her narrative path involves shifting allegiance from Grand Paladin to the Sealing Faction, joining allies like Benika Takatori and Yōsuke Hitsujitani as the conflict against the Nebula government escalates. After a five-year time skip, she continues battling alongside former allies against new threats. Her development stems primarily from her relationship with Miu and her evolving role within the faction conflict.