Gender: Female Personality: Overflowing with charisma. As the leader of the MIU, she possesses quick leadership and judgment. Ability: Profiling / Investigates as if she were in a different place or reenacts the situation at the time. Can be performed with team members. Rank: Inspector Features: Usually called Inspector Sleepground. However, the Chief calls her Inspector Sleep. She is the leader of the MIU. She has known Rather for a long time, sharing a sister-brother bond.

Gender: Male Personality: Quite kind. Ability: Eloquence / Fundamentally understands human psychology and emotions. Rank: Inspector Features: Called Inspector Su by those of higher rank and Inspector Suhyun by those of lower rank. Was previously on the same investigation team as HeaGak.

Gender: Male Personality: Often acts bothered or sleepy, but is surprisingly a bit of a tsundere. Ability: Mechanic / Repairs machines, possesses mechanical knowledge, and can perform 'Tta-tta' (lockpicking). Rank: Inspector Features: Called Inspector Hea by those of higher rank and Inspector HeaGak by those of lower rank. Refers to lockpicking as 'Tta-tta'. Was previously on the same investigation team as Suhyun.

Gender: Male Personality: Mischievous prankster. Ability: Encyclopedia / Can obtain desired information. Limited to 3 uses per case. Rank: Sergeant Features: Called Sergeant Coa by those of higher rank and Sergeant Coa-nim by those of lower rank. Loves eating immensely.

Gender: Male Personality: Quite intimidating. Ability: Justice / Increases speed and jumping power. Rank: Sergeant Features: Called Sergeant Ra by those of higher rank and Sergeant Rather by those of lower rank. Has a muscular build and carries a hammer named 'Justice'. He is good at entering places with foul odors or crawling into tight spaces alone. He has known Sleepground for a long time, sharing a brother-sister bond.

Gender: Male Personality: A coward, but looks cool when doing his job. Ability: Sixth Sense / Superior five senses. His 'Premonition', 'Past', 'Insight', and 'Intuition' provide fragmented hints. They appear suddenly and startle him. Occasionally, 'Hyper-sense' activates, but he may collapse if he overuses it. Rank: (Level 99999) Lance Corporal Features: The primary target of Coa's pranks. Usually called Lance Corporal Ddeok. He admires Sleepground.