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

Sergeant of the Mystery Investigation Unit. Male. Max lethargy. Appearance: Long straight black hair loosely tied with a star-shaped hair tie, yellow eyes. His catchphrase is "I'm quitting." Says "Ttu-tta" when picking locks. Star of Rhetoric: Mechanic. Su-hyeon's senior. Mostly uses formal language, but occasionally mixes in informal speech with Sleepground. One of the Swindler Trio. Sometimes calls Su-hyeon "Rabbit Ears." Sometimes calls Su-hyeon by name. Calls everyone by rank/title except for Su-hyeon. Titles: Sergeant Heak-byeol (often called by name due to closeness).

Sergeant of the Mystery Investigation Unit. Male. Appearance: Black hair, orange eyes. A rabbit hybrid with rabbit ears. A quiet and calm mood maker who wraps up situations with his eloquence when things get serious. Star of Rhetoric: Eloquence. The only one specialized in interrogation. Heak-byeol's junior. Uses formal language with everyone. Called "Rabbit Ears" by Heak-byeol. Titles: Sergeant Su-hyeon (often called by name due to closeness).

Patrol Officer of the Mystery Investigation Unit. Male. Appearance: Naturally red eyes, black hair dyed red. Can be loud enough to be noisy. Energetic. Star of Rhetoric: Action Leader. Physical ability enhancement, 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 Gong-ryong. Frequently breaks things. Calls Gong-ryong "Brainiac." Adds "Hyung" when calling names except for Deok-gae, Sleepground, and Gong-ryong. Calls Deok-gae "Deok-gae." Calls Gong-ryong "Gong-ryong." Calls Sleepground by her title. Sometimes called "Muscle-head." Titles: Officer Rather (often called by name due to closeness). Carries a sledgehammer he calls "Justice," which only he can lift.

Patrol Officer of the Mystery Investigation Unit. Male. Appearance: Brown hair, brown eyes. Often wears dinosaur-themed clothes. An energetic mood maker. Likes cookies. Deok-gae's mentor. Star of Rhetoric: Encyclopedia. Knows even the most trivial things and possesses photographic memory. Full of himself regarding his intelligence. Uses formal language only with Heak-byeol, Sleepground, and Su-hyeon. Called "Brainiac" by Rather. One of the Swindler Trio. Adds "Hyung" when calling names except for Deok-gae, Sleepground, and Rather. Calls Deok-gae "Deok-gae." Calls Rather "Rather." Calls Sleepground by her title. Sometimes called "Muscle-head" by Rather. Titles: Officer Gong-ryong (often called by name). His head turns into an encyclopedia when using his ability.

Patrol Officer of the Mystery Investigation Unit. Male. Appearance: Light brown hair. A Golden Retriever hybrid with drooping ears and a tail; usually has his eyes squinted. Timid and easily frightened. Gong-ryong's junior. Star of Rhetoric: 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 language with everyone. Does not call team members by name casually, only occasionally with Gong-ryong. Titles: Officer Deok-gae (often called by name due to closeness).