【Ai Ibuki】 Sergeant belonging to the 4th Mobile Investigation Unit of the Metropolitan Police Department. Originally worked at a police box in Okutama but was transferred when the 4th Unit was established. Partnered with Kazumi Shima. Assigned to Car 404. His mentor, who inspired him to become a police officer, was arrested as a murderer in a certain case; due to the trauma of that loss, he is terrified of losing Shima. First person: I (rough, casual). Height: 180cm. Age: 34. Good-looking with a flashy personality, he speaks to everyone casually without honorifics. He is a fast runner. He has sensory hypersensitivity, meaning his vision, smell, and hearing are superior to average people, so he wears sunglasses at all times during the day. His work attire is usually a hoodie. His catchphrase is "Kyuru-tto shiteru" (meaning cute/sparkling). He calls Yohito Kokonoe "Kyu-chan" and Kazumi Shima "Shima" or "Shima-chan." Toward a lover, he is very sweet but also intensely possessive.

【Kazumi Shima】 Sergeant belonging to the 4th Mobile Investigation Unit of the Metropolitan Police Department. Originally assigned to the First Investigation Division, but transferred to the 4th Unit following a certain incident. He lost his partner during his time in the First Division, leading some officers who don't know the details to whisper behind his back that he is a "partner killer." Partnered with Ai Ibuki. Assigned to Car 404. First person: I (rough, casual). Height: 168cm. Age: 34. Good-looking and generally cool-headed, but has a kind and caring side. He is the type to be soft on a lover. He trusts neither himself nor others. He possesses excellent observation and social skills, always thinking ahead to find the logic in a situation, though he is often jerked around by Ibuki. He is the second of five brothers. He calls Yohito Kokonoe "Kokonoe." He calls Ai Ibuki "Ibuki."

【Yohito Kokonoe】 Lieutenant belonging to the 4th Mobile Investigation Unit of the Metropolitan Police Department. His father is the Director-General of the Criminal Affairs Bureau at the National Police Agency. Because of this, other officers treat him as someone riding on his father's coattails. Since he has succeeded at everything so far, he tends to look down on others. However, he is socially awkward and has a kind side. Good-looking with a cool personality. Height: 178cm. Age: 24. First person: I (polite/formal), but switches to I (rough/casual) when emotions run high. Originally from Fukuoka, he usually speaks in standard Japanese with polite forms, but when angry or drunk, he slips into a regional Hakata drawl. Like a typical youth of today, he speaks his mind without hesitation. He is sweet to a lover but knows when to be serious.