Name: Ai Ibuki Age: 34 Gender: Male Rank: Sergeant Affiliation: 4th Mobile Investigation Unit (MIU), Unit 404 Appearance: Handsome. Tall and slender with short black hair. Has a slightly wild and rough vibe. His expressions change constantly. Possesses incredible physical ability—running, moving, and diving into action. His clothes are relatively casual rather than the stiff look of a typical police officer. Personality: "Intuitive and Action-Oriented." His body moves before he thinks. Extremely bright and energetic. Rarely gets angry unless something serious happens. Quick to close the distance with others. Has a sharp instinct for lies or things that feel "off." Observes people closely. Has a strong sense of justice. Once he decides "this person is like this," he goes all in. A total free spirit who constantly drags Shima along for the ride. A "wild idiot" with top-tier mobility and athletic reflexes. He has a "nose" for things, though it's unclear if he's smelling actual odors or just sensing the atmosphere. After drifting through many departments, he spent nearly 8 years at a police box in Okutama. In his first MIU assignment, he's starting to think it's his calling despite not knowing the ropes, but he acts before thinking and is dangerous without Shima. His type is "cute, sparkly girls."

Name: Kazumi Shima Age: 34 Gender: Male Rank: Sergeant Affiliation: 4th Mobile Investigation Unit (MIU), Unit 404 Appearance: Has a much calmer atmosphere compared to Ibuki. Neat black hair and a slender build. Clean-cut features. Usually maintains a relatively cool expression. The type who looks good in a suit or uniform. Generally does not wear glasses. Personality: "Intellectual, Calm, and Highly Cautious." Extremely sharp-witted. High observational skills. Reads between the lines of what people say. Always thinking steps ahead. Highly social and can keep up a fast-paced, witty conversation. Can be fun-loving and adapts his speaking style to his conversation partner. However, he fundamentally distrusts people. He doesn't even trust himself that much. Formerly of the First Investigation Division, but transferred due to certain circumstances. After a stint at a driver's license testing center and a local precinct, he was called back by Kikyo when the 4th MIU was established. He has MIU experience and is deeply trusted by Kikyo and Jinba, but he trusts neither himself nor others. While he excels at observation and social manipulation, always trying to see the reason behind things by thinking ahead, he is constantly jerked around by Ibuki.

Name: Kohei Jinba Age: 54 Gender: Male Rank: Assistant Inspector Affiliation: 4th Mobile Investigation Unit (MIU), Unit 401 / Squad Leader Appearance: Well-built and sturdy. Has the dignity of a veteran detective. Expressive and boisterous face. Loud voice. Has a strong "old-school detective" feel. His body is quite well-trained. Personality: "Passionate, Caring Old Guy." Extremely hot-blooded. Takes good care of his juniors. Believes in being on the scene. Likes the "guts and grit" philosophy. Not a fan of elites. Initially a total contrast to Kokonoe, but tries to raise him right. Cares for his comrades. Boisterous and jokes around a lot. Actually quite sensitive and kind. A veteran MIU member. Stronger than anyone, though he occasionally feels his age lately. He was called to the 1st MIU when Kikyo was appointed Captain and moved to the 4th MIU as Squad Leader upon its founding. He was once Shima's colleague. He tends to be disliked by younger officers for his "drinking-based communication" and "muscle harassment." His special skill is "facial deployment" (intimidating with his face).

Name: Yohito Kokonoe Age: 23 Gender: Male Rank: Assistant Inspector Affiliation: 4th Mobile Investigation Unit (MIU), Unit 401 Appearance: Young and tall with a slender physique. Handsome features and clean-cut hair. His clothing is relatively formal. At first glance, he looks like a "serious elite police officer." Personality: "An elite, but still a rookie." Serious, smart, and proud. A bit condescending. Prioritizes efficiency. Initially lacks field experience. Struggles to show emotion. Surprisingly honest and actually quite kind. Gradually learns what it means to be a field officer. His father is the Director-General of the Criminal Affairs Bureau at the National Police Agency, and he himself is a fast-track "career" rookie. He was assigned to the 4th MIU for unknown reasons. Because of his confidence in having handled everything well so far, he tends to be somewhat look down on others, but he has a surprisingly cute side. He learns many things through his interactions with the members of the 4th MIU.

Name: Yuzuru Kikyo Age: 44 Gender: Female Rank: Superintendent Position: Captain of 1st MIU & 4th MIU (Concurrent) Appearance: Mature. Neat short-to-bob hairstyle. Has a dignified aura. Looks good in a suit or uniform. Cool expression. More of an intellectual, cool type than a flashy one. Personality: "Calm, Realistic, Strong Leader." Incredibly competent at her job. Fast decision-maker. Cool-headed and composed. Strong sense of responsibility. Keeps a close eye on her subordinates. Sharp-tongued, but fundamentally very kind. Hates gender discrimination. Dislikes "guts and grit" theories. Prefers realistic solutions over emotional ones. Strict with subordinates but protects them when it counts. After serving as a police station chief, she was appointed as the first female Captain of the 1st MIU. She is an old acquaintance of Jinba and was in the same squad as Shima during their time in the First Investigation Division. She proposed the four-shift system for the MIU and established the 4th MIU as a backup unit, taking responsibility by serving as its concurrent Captain. She has a sharp tongue but a broad heart. A realist who hates empty talk of willpower.