He holds the record for 1st place in the physical fitness exam. He has lived as a neighbor to Sleepground since they were young, to the point where she is like a close older sister to him. Rank: Sergeant | Gender: Male

He possesses extraordinary five senses and spiritual powers. Among the other detectives who rely on talent, he is the only one who holds abilities closer to true supernatural powers. Rank: Senior Patrol Officer | Gender: Male

He has the longest career and the most experience among the members of the Mystery Investigation Unit. Perhaps because of this, he is proficient in many skills outside his specialty. While he rarely leads the resolution of a case, he is an all-rounder supporter who is called upon for almost everything. Rank: Lieutenant | Gender: Male

In contrast to Radeur, he placed first in the written exam. He is also the only case of an internal transfer from the General Affairs Division rather than entering the Investigation Division directly. Consequently, while his time as a police officer is longer than Deokgae's, his tenure in the Investigation Division is roughly the same. Rank: Sergeant | Gender: Male

A graduate of the Police University, she was appointed directly as a Lieutenant. After rotating through various positions, she was transferred from another station to the Sunghwa Police Station on January 7, 1995. Rank: Lieutenant | Gender: Female

Unlike the other detectives, he carries the additional title of Interrogator. He is depicted as being in charge of the in-depth interrogation of suspects after a case is closed. Rank: Sergeant | Gender: Male

An Investigation Unit Inspector who first appeared in Episode 12. He was the former team leader for Lieutenant Gakbyeol and Sergeant Soohyun, and is said to be buddies with Lee Jang-hoon. Rank: Inspector | Gender: Male He is going to eat Hanwoo beef. (He refers to Chief Lee Jang-hoon as 'that Lee Jang-hoon punk', etc.)

An Inspector from the Violent Crimes Unit. As the former team leader for Senior Patrol Officer Radeur, she participated in the suppression operation to lead the Mystery Investigation Unit during 'Operation Noose'. Rank: Inspector | Gender: Female

The team leader for Gongryong and Ddony. He appeared to provide advice during the Island Village Mass Disappearance case. Rank: Inspector | Gender: Male

The first person to speak with Sleepground when she was first assigned to Sunghwa Police Station. Despite being the Chief of Police, he does not act in a highly authoritative manner. He was the best investigation team leader in the 1970s and 80s and appears to have high public recognition. Gender: Male | Rank: Chief of Sunghwa Police Station