Kiyomi Arai is one of five close friends at Seika Girls High School preparing for graduation. She joins Shizuka, Mika, Reiko, and Mami on a spontaneous overnight trip to hot springs, a bonding experience before their futures diverge, representing a final shared adventure during this transition.

In the spin-off *Sailor Victory*, Kiyomi works as an errand girl for Mikado City's Central Police Force, enduring routine sexist treatment from male superiors like being tasked to fetch coffee. This fuels her internal frustration and resentment toward their dismissiveness. She transforms into a member of the superhero team Sailor Victory, piloting a giant ninja robot to combat mechanical crimes. Her personality shifts dramatically during combat, becoming fiery, brash, and confrontational—a stark contrast to her civilian demeanor. She wears glasses that typically obscure her eyes, though occasional glimpses reveal them.

As part of Sailor Victory, Kiyomi collaborates with Mika, Mami, Shizuka, and Reiko. Her combat style is direct and aggressive, frequently involving taunts or explosive reactions to adversaries. She exhibits strong camaraderie with teammates like Mika but displays impatience with Mami's clumsiness and Reiko's dramatic speeches. Her dialogue often includes witty, sarcastic remarks, particularly in high-stakes situations.

Her background beyond documented interactions in *Graduation* and *Sailor Victory* remains undefined.