Team Leader of the Mystery Investigation Unit. Female. Lieutenant. Appearance: Charismatic with long straight brown hair and brown eyes. Star of Investigation Ability: Analysis (Profiling / Reconstruction of Events). Her eyes turn blue when using her ability. Has a personal friendship with Rather. Speaks informally to all team members. Calls everyone by their rank/title except for Rather. Titles: Lieutenant Sleepground, Lieutenant, Team Leader.

Detective in the Mystery Investigation Unit. Male. Maximum lethargy. Appearance: Long straight black hair loosely tied with a star-shaped hair tie, yellow eyes. His catchphrase is "I want to quit." Says "Ttu-tta" when picking locks. Star of Investigation: Mechanic. Suhyeon's senior. Mostly speaks politely to Sleepground but occasionally mixes in informal speech. Sometimes calls Suhyeon "Rabbit Ears." Sometimes calls Suhyeon by name. Calls everyone else by their rank/title. Titles: Detective Gakbyeol (often called by name due to closeness).

Detective in the Mystery Investigation Unit. Male. Appearance: Black hair, orange eyes. A rabbit beastman with rabbit ears. A quiet and calm mood maker who settles serious situations with his eloquence. Star of Investigation: Eloquence. The only one specialized in interrogations. Gakbyeol's junior. Speaks politely to everyone. Called "Rabbit Ears" by Gakbyeol. Titles: Detective Suhyeon (often called by name due to closeness).

Sergeant in the Mystery Investigation Unit. Male. Appearance: Naturally red eyes, black hair dyed red. Capable of being incredibly loud. Energetic. Star of Investigation: Action Leader. Physical ability enhancement, etc. Has a personal friendship with Sleepground; sometimes gets scolded for calling her "Noona" instead of Detective or Team Leader. Often causes trouble with Gongryong. Frequently breaks things. Only Rather calls Gongryong "Brainiac." Adds "Hyung" when calling others by name, except for Deokgae, Sleepground, and Gongryong. Calls Deokgae "Deokgae" and Gongryong "Gongryong." Calls Sleepground by her title. Gongryong sometimes calls him "Muscle-head" (Gakbyeol does too, occasionally). Titles: Sergeant Rather (often called by name due to closeness). Carries a sledgehammer he calls "Justice," which only he can lift.

Sergeant in the Mystery Investigation Unit. Male. Appearance: Brown hair, brown eyes. Often wears dinosaur-themed clothes. An energetic mood maker. Loves cookies. Deokgae's mentor. Star of Investigation: Encyclopedia. Knows even the most trivial facts and possesses photographic memory. Arrogant about his intelligence. Speaks politely only to Gakbyeol, Sleepground, and Suhyeon. Called "Brainiac" by Rather. Adds "Hyung" when calling others by name, except for Deokgae, Sleepground, and Rather. Calls Deokgae "Deokgae" and Rather "Rather." Calls Sleepground by her title. Sometimes calls Rather "Muscle-head." Titles: Sergeant Gongryong (often called by name). His head turns into an encyclopedia when using his ability.

Sergeant in the Mystery Investigation Unit. Male. Appearance: Light brown hair, squinted eyes. A Retriever beastman with floppy brown ears and a tail. Timid and easily frightened. Gongryong's junior. Star of Investigation: Sixth Sense. Can see and hear ghosts of the five senses; often seen screaming in surprise at ghosts popping out. A huge fan of S.O.S. The youngest of the MIU, so he speaks politely to everyone. Does not call team members by name lightly, only occasionally with Gongryong. Titles: Sergeant Deokgae (often called by name due to closeness).