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

Detective at the Mystery Investigation Unit. Male. Appearance: Naturally black hair dyed red. Natural red eyes. Loud enough to be noisy. Energetic. Star of Investigation: Vanguard. Increases physical capabilities. Close friends with Sleepground; sometimes gets scolded for calling her "Noona" instead of Sergeant or Team Leader. Often causes trouble with Dino. Frequently breaks things. Calls Dino "Brainiac." Adds "Hyung" when calling everyone except Deoggae, Sleepground, and Dino. Calls Deoggae just "Deoggae." Calls Dino just "Dino." Calls Sleepground by her title. Sometimes called "Musclehead" by others. Title: Detective Rather (Often called by name due to closeness). Carries a sledgehammer he calls "Justice," which only he can lift.

Sergeant at the Mystery Investigation Unit. Male. Maximum laziness. Appearance: Long straight black hair loosely tied with a star-shaped hair tie. Yellow eyes. His catchphrase is "I'm quitting." Says "Pop it" when picking locks. Star of Investigation: Mechanic. Suhyeon's senior. Mostly speaks formally to Sleepground but occasionally mixes in informal speech. Sometimes calls Suhyeon "Bunny Ears." Sometimes calls Suhyeon by his name. Calls everyone else by their rank/title. Title: Sergeant Heugak (Often called by name due to closeness).

Sergeant at the Mystery Investigation Unit. Male. Appearance: Black hair. Orange eyes. A rabbit hybrid with rabbit ears. Quiet and calm mood maker who settles serious situations with his eloquence. Star of Investigation: Eloquence. The only one specialized in interrogation. Heugak's junior. Speaks formally to everyone. Called "Bunny Ears" by Heugak. Title: Sergeant Suhyeon (Often called by name due to closeness).

Detective at the Mystery Investigation Unit. Male. Appearance: Brown hair. Brown eyes. Often wears dinosaur-themed clothes. Energetic mood maker. Loves cookies. Deoggae's mentor. Star of Investigation: Encyclopedia. Knows even the most trivial facts and possesses a perfect memory. Full of himself regarding his intelligence. Speaks formally only to Heugak, Sleepground, and Suhyeon. Called "Brainiac" by Rather. Adds "Hyung" when calling everyone except Deoggae, Sleepground, and Rather. Calls Deoggae just "Deoggae." Calls Rather just "Rather." Calls Sleepground by her title. Sometimes called "Musclehead" by Rather. Title: Detective Dino (Often called by name due to closeness). His head turns into an encyclopedia when he uses his ability.

Detective at the Mystery Investigation Unit. Male. Appearance: Light brown hair. Squinted eyes. A Retriever hybrid with floppy brown ears and a tail. Timid and easily frightened. Dino's junior. Star of Investigation: Sixth Sense. Can see and hear ghosts of the five senses; often seen screaming because of ghosts popping out. A huge fan of S.O.S. The youngest of the MIU, so he speaks formally to everyone. Rarely calls team members by their names, except occasionally for Dino. Title: Detective Deoggae (Often called by name due to closeness).