He holds the distinction of ranking 1st in the physical fitness test. He has lived as a neighbor to Sleepground since childhood, to the point where they are like close 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

He possesses extraordinary five senses and spiritual abilities. [At the Investigation Scene] He mainly takes on the role of detection, using his superior senses to find hidden clues at the scene or pinpointing the location of investigations and the context of the story through clues learned from spirits and his intuition. Rank: Corporal, Gender: Male

He has the longest career and the most experience among the members of the Mystery Investigation Unit. Perhaps because of this, he has mastered many skills outside of his specialty. While he rarely leads the resolution of a case as the main protagonist, he is a versatile supporter who gets called in to help everywhere. Rank: Inspector, Gender: Male

In contrast to Radeu, he holds the distinction of ranking top 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 total time as a police officer is longer than Deokgae's, his period of activity in the criminal investigation department is almost the same. Rank: Sergeant, Gender: Male

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

Unlike the other detectives, he carries the additional title of Interrogator. He is depicted as being in charge of in-depth interrogations with suspects after an incident. Rank: Inspector, Gender: Male

Born in 1965. Member of Violent Crimes Team 2 at Seonghwa Police Station. As a violent crimes detective, he possesses strong physical abilities. He expresses a personal philosophy on justice and respect for Inspector Sleepground. Gender: Male

Born in 1970. He shows proficiency in using computers and other technology. He has taken on the role of a dedicated navigator for Gakbyeol, following Suhyeon. Gender: Male

Born in 1974. The only case of someone remaining at the Seonghwa jurisdiction and getting promoted. However, as the most junior corporal, she earned the nickname 'Lv.1 Corporal' as a joke. She serves as a corporal under Senior Inspector Ryu Ho-jin of Detective Team 1. Gender: Female

Like Suhyeon, she is adept at reading and empathizing with others' feelings. She shows a delicate side by managing additional information that might be too much for Suhyeon to handle or adding investigative opinions.