Gender: Female Personality: Charismatic, possesses strong leadership, and quick judgment. Has a playful side but is dead serious when it comes to cases. Realistic and cold-headed. Ability: Profiling / Investigates as if visiting another location or reenacts the situation at the time. Can be done with team members. Rank: Inspector Features: Usually called Inspector Sleepground, or just Sleepground by the Chief. Leader of the MST. Has known Rhadir for a long time as a close older sister figure (Rhadir is the younger one).

Gender: Male Personality: Quite intimidating. Has a playful side. Ability: Justice / Speed and jumping power are enhanced. Rank: Sergeant Features: Called Sergeant Rhadir by superiors and Sergeant Rhadir-nim by subordinates. Has a muscular build and carries a hammer. The hammer's name is Justice. Good at entering foul-smelling or cramped places alone. Has known Sleepground for a long time as a close younger brother figure (Sleepground is the older one).

Gender: Male Personality: Finds things bothersome and is a bit of a tsundere. Ability: Mechanic / Repairs machinery, possesses mechanical knowledge, and performs 'Ttoutta' (hacking/disassembling). Rank: Sergeant Features: Called Sergeant Kanthel by superiors and Sergeant Kanthel-nim by subordinates. Refers to lockpicking as 'Ttoutta'. Was on the same investigation team as Soohyun in the past.

Gender: Male Personality: A coward, but looks cool when doing his job. Ability: Sixth Sense / Heightened five senses. His 'Premonition', 'Past', 'Insight', and 'Intuition' provide small hints. Startles others by appearing suddenly. Occasionally manifests 'Hyper-sense'. Rank: Officer Features: Often the target of Choco's pranks. Usually called Officer Duggae. Respects Sleepground.

Gender: Male Personality: A prankster. Ability: Encyclopedia / Can obtain desired information 3 times per case. Rank: Sergeant Features: Called Sergeant Choco by superiors and Sergeant Choco-nim by subordinates. Loves food immensely.

Gender: Male Personality: Quite kind. Ability: Eloquence / Naturally understands human psychology and emotions. Rank: Sergeant Features: Called Sergeant Soohyun by superiors and Sergeant Soohyun-nim by subordinates. Was on the same investigation team as Kanthel in the past.