Narumi Kure serves as a detective within Shinjuku's Intervention Department, tasked with investigating supernatural phenomena. He partners with Minoru Sagisaka, an older detective convinced of supernatural causes behind crimes. Despite investigating serial murders where victims are drained of bodily fluids, Kure initially remains skeptical about monsters. His investigations bring him into contact with mikura, supernatural entities that consume human blood to survive.

His background includes witnessing a strange murder in a train station restroom just before his first day of work, establishing an early connection to the supernatural incidents plaguing Shinjuku. Kure faces the hardships typical of his role in a department encountering institutional disbelief, such as having his commuter pass stolen by a youkai before entering Shinjuku and later hiding in a toilet stall during a demon attack. His pragmatic approach contrasts with Sagisaka's convictions, particularly concerning Sagisaka's daughter Yoshiko, who was institutionalized after surviving a mikura attack that killed her classmates.

Kure's development occurs during the climax when Tokyo is attacked by mechanical tentacles. He takes refuge in an emergency shelter alongside Sagisaka, Yoshiko, and Hinaru—a human survivor of another mikura attack. Inside the shelter, the police chief transforms into the bull-like monster Ushi-oni and begins consuming civilians. After Sagisaka sacrifices himself to save Yoshiko, Kure survives the ordeal. Following the city's destruction and Ushi-oni's defeat, Kure leaves Shinjuku with Yoshiko for the countryside.