Koyori Kokubunji, a 17-year-old student, model, and cosplayer, works at the Kiri Pro talent agency alongside Komugi Nakahara. As a traditional idol, she achieves greater professional success than Komugi, partly due to her advantageous physical measurements, though she openly admires Komugi's ability to wear cute costumes. Her personality remains consistently friendly, sympathetic, and free of envy or malice, fostering positive industry relationships.

Periodically, Koyori loses consciousness and undergoes an involuntary transformation into her alternate identity, Magical Maid Koyori. In this state, her personality reverses completely, becoming arrogant and hostile. She adopts a noblewoman's laugh and, in the Japanese version, appends the verbal tic "de gozaimasu wa" to her speech. As the primary antagonist, she infects innocent people with viruses under the command of Ungrar, the King of Viruses from Vaccine World. Her abilities include transforming famous Japanese landmarks like Tokyo Big Sight into weaponized mecha to advance her attacks.

Magical Maid Koyori is accompanied by Posokichi, a quiet raccoon sidekick she trains to speak. She views Komugi and Komugi's sidekick Mugimaru as rivals, frequently voicing frustration after defeats at their hands. Following these confrontations, she reverts to her original form with no memory of her actions as Magical Maid Koyori. This cyclical pattern of transformation, conflict, and amnesia defines her character arc across the original OVA series and its sequel, *Nurse Witch Komugi-chan Magikarte Z*.

Her design features dark blue hair, blue eyes, and occasional elements like cute little fangs. Merchandise emphasizes her Magical Maid persona, including figures in variant costumes. She does not appear in the 2016 reboot *Nurse Witch Komugi R*.