Kyōichi Sakaki leads the Shinjuku Ward Nocturnal Community Relations Division, managing responses to supernatural incidents involving beings called Anothers. He presents a professional image, wearing glasses and sporting a well-trimmed hairstyle reflecting his past as a popular host. Known for womanizing and enjoying alcohol, he maintains strong work ethics, avoiding personal entanglements during duty to prioritize division responsibilities.

His motivations are shaped by personal history. Orphaned young, he was raised by his elder sister. Seventeen years before the series' events, an Another abducted his sister after eye contact, leaving him with unresolved anger and loss. This drives his commitment to the division's mission. Supervisor Reiji Senda recruited him based on this background and his skills.

As the division's primary field operator, Sakaki takes direct action during incidents. His approach contrasts with colleagues who favor negotiation or gadgets; he employs physical intervention to neutralize threats, a pragmatic style rooted in his trauma with hostile Anothers. His backstory and quest to discover his sister's fate surface during operations, revealing emotional stakes beyond bureaucratic duties.

He appears in supplemental media, including OVAs focusing on cases like "Fukurokouji to Anoko to Ore to." His character consistently balances a charming host persona with dedicated public service, resolving supernatural conflicts while privately seeking answers about his sister's disappearance.