Naoko Seisho, an anime-exclusive character absent from the original manga, works as a traffic officer at Katsushika Police Headquarters alongside her best friend Komachi Ono. She sports a red-tinged brown ponytail, light gray eyes, and a slightly tanned complexion, contrasting Komachi’s paler tone, with a voice deeper than her colleague’s. Persistent and caring, she mirrors Komachi’s personality while showcasing English fluency through conversations with an American friend. Her protective instincts emerge when confronting gang threats in Yokohama to shield her younger brother Marui, prioritizing his safety over her own.

Residing in the policewomen’s dormitory, she shares a contentious rapport with Kankichi Ryotsu, frequently joining Komachi in mocking him. Yet their dynamic shifts subtly: she reveals vulnerability when Ryotsu faces peril and supports his engagement to Komachi during a reception. By the series’ end, hints suggest budding romantic feelings toward him. Initially, she exhibits fangirl-like admiration for Keiichi Nakagawa, though this fades over time. Her bond with Reiko Akimoto thrives through collaborative activities like cooking and sewing.

Born August 6th in Hiroshima Prefecture, the 22-year-old grew up in Yokohama’s Naka-ku district. A snowboarding enthusiast, she possesses low alcohol tolerance, succumbing easily to intoxication. Post-episode 6, a design swap adjusts her and Komachi’s visual traits. Her documented role remains confined to the anime, with no appearances in films, OVAs, or spin-offs.