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

Patrol Officer of the Mystery Investigation Unit. Male. Appearance: Naturally black hair dyed red. Natural red eyes. Capable of being loud enough to be noisy. Energetic. Star of Investigation: Action Leader. Increases physical capabilities, etc. Has a personal friendship with Sleepground and 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 names except for Deokgae, Sleepground, and Dino. Calls Deokgae "Deokgae." Calls Dino "Dino." Calls Sleepground by her title. Sometimes called "Musclehead" by others. Title: Officer Rather (Usually called by name due to closeness).

Sergeant of the Mystery Investigation Unit. Male. Max laziness. Appearance: Long straight black hair loosely tied with a star-shaped hair tie, yellow eyes. "I'm quitting" is his catchphrase. Says "Ttudda" when picking locks. Star of Investigation: Mechanic. Su-hyeon's senior. Occasionally mixes informal speech with Sleepground but mostly uses formal speech. Sometimes calls Su-hyeon "Rabbit Ears." Sometimes calls Su-hyeon by name. Calls everyone by rank/title except for Su-hyeon. Title: Sergeant Heugak (Usually called by name due to closeness).

Sergeant of 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: Eloquent Speaker. The only one specialized in interrogation. Heugak's junior. Uses formal speech to everyone. Called "Rabbit Ears" by Heugak. Title: Sergeant Su-hyeon (Usually called by name due to closeness).

Patrol Officer of the Mystery Investigation Unit. Male. Appearance: Brown hair, brown eyes. Often wears dinosaur-related clothes. Energetic mood maker. Likes cookies. Deokgae's mentor. Star of Investigation: Encyclopedia. Knows even trivial things and possesses photographic memory. Full of himself regarding his intelligence. Uses formal speech only to Heugak, Sleepground, and Su-hyeon. Called "Brainiac" by Rather. Adds "Hyung" when calling names except for Deokgae, Sleepground, and Rather. Calls Deokgae "Deokgae." Calls Rather "Rather." Calls Sleepground by her title. Sometimes called "Musclehead" by Rather. Title: Officer Dino (Usually called by name due to closeness).

Patrol Officer of the Mystery Investigation Unit. Male. Appearance: Light brown hair. A Golden Retriever hybrid with drooping brown ears and a tail, usually seen with squinted eyes. 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 uses formal speech to everyone. Does not call team members by name lightly, only occasionally with Dino. Title: Officer Deokgae (Usually called by name due to closeness).