Ranked 1st in the physical fitness test. He has lived as a neighbor to Sleepground since they were young, to the point where they are like siblings. In Season 1, Episode 6, a flashback through a family photo revealed that his current hairstyle is the result of hair dye and hard wax. His natural hair color is black, not red. Rank: Sergeant | Gender: Male

Possesses extraordinary five senses and spiritual powers. Among the other detectives whose abilities are closer to talent, he is the only one with powers that are truly supernatural. However, except for his sensory abilities, they do not occur under his conscious control. [At the Investigation Scene] He plays a detection role, finding hidden clues at the scene with his superior senses or pinpointing the location and context of the story through clues learned from spirits and intuition. Rank: Corporal | Gender: Male

Has the most seniority and experience among the members of the Mystery Investigation Unit. Perhaps because of this, he has mastered many skills outside his specialty. While he rarely leads the resolution of a case as the main protagonist, he is an all-rounder supporter who is called upon for almost everything. In Season 1, Episode 10, Seo Hee-young called him handsome, and given that Officer TT respects him and has high favorability, he appears to be a quite good-looking man within the world-building. Rank: Lieutenant | Gender: Male

Unlike Rader, he ranked 1st in the written exam. He is also the only case who did not enter the investigation department directly but transferred from the general affairs department. Therefore, while his overall career as a police officer is longer than Deokgae's, his time in the criminal investigation department is roughly the same. Rank: Sergeant | Gender: Male

A graduate of the police academy, she was appointed directly as a Lieutenant. After rotating through various positions, she was transferred from another station to Seonghwa Police Station on January 7, 1995. Before the formation of the investigation unit, she seemed to have focused on solo investigations and did not appear to have a very positive impression of team activities. Rank: Lieutenant | Gender: Female

Corporal Shin Seung-ah: Female. Su-hyeon's subordinate. Lieutenant Kwon Min-gu: Male (Violent Crimes Team 2). Rader's senior. [Married with a daughter] Corporal Ttoni: Female. Gongryong's junior. Corporal Kim Jun-yeop: Male. Gakbyeol's 'navigator'. Lieutenant Oh Jun-hyeon: Male. Deokgae's senior.