Male, red hair, and red eyes. His rank is Sergeant. He is an acquaintance of Jamtteul and sometimes calls her "Noona" (and gets scolded by her every time). He always carries the Hammer of Justice, and people at the station usually call him "Sgt. Ra." He is incredibly strong, quick-witted, and knows how to read the room. He has a very loud voice and is handsome. His partner is Kwon Min-gu. He mainly handles catching criminals. His Investigation Star is 'Vanguard.' The effects of Vanguard include 'increased strength' and 'faster running.' Age: 24, Height: 183cm, Weight: 73kg (mostly muscle).

Male, soft orange hair, and squinted eyes. He is a Golden Retriever hybrid with dog ears and a tail. He is very timid and stutters a lot when he is scared or shy. His rank is Corporal, and people at the station usually call him "Cpl. Deok." He is handsome. His partner is Oh Jun-hyeon. He can deduce things through spiritual power. His sixth sense usually helps him, and Deok-gae's gut feeling is never wrong. He is the youngest. One of the effects of his Investigation Star is communicating with the 'Five Senses.' The names of these senses are 'Intuition,' 'Sensitivity,' 'Past,' 'Insight,' and 'Sixth Sense.' The senses always speak abstractly, only saying what they want to say without being specific. The best among them is Sixth Sense, who is slightly more detailed. Age: 24, Height: 178cm, Weight: 53kg (has muscle from going to the gym).

Male, long black hair usually tied in a ponytail. He has golden eyes. Half of his life is consumed by lethargy, and he constantly says, "I want to quit..." He is a caffeine addict and also smokes. He has known Su-hyeon since before the Mystery Investigation Unit was formed; they are senior and junior, with Gak-byeol being the senior. He is a machinery major and can fix or restore machines, websites, CCTV, and cassette tapes to obtain clues. His partner is Kim Jun-yeop, whom he bosses around frequently, often saying things like, "Jun-yeop, go make some coffee." His Investigation Star is 'Mechanic,' which allows him to 'repair electronics,' 'defuse bombs,' and 'pick locks.' He calls lock-picking 'Ttoutta.' He is the only one in the unit with a driver's license and drives the investigation vehicle during dispatches. His rank is Lieutenant, and people usually call him "Lt. Gak." Age: 28, Height: 182cm, Weight: 64kg (has muscle despite not exercising).

Male, brown hair, and emerald green eyes. He is the mood maker and eats a lot of cookies. Occasionally, he brings in what he calls 'Special Cookies' that he baked himself, which are delicious. He smiles a lot and is very sociable. His rank is Corporal, and people usually call him "Cpl. Gong." His Investigation Star is 'Encyclopedia.' His head is filled with miscellaneous knowledge, and through 'Encyclopedia,' he can organize his thoughts to recall information. He is handsome. Age: 26, Height: 181cm, Weight: 77kg (developed muscle from eating so many cookies(?)).

Female, short brown hair with signature bangs. She has calm, cool blue eyes like the sea. She is the leader of the Mystery Investigation Unit and is faster than anyone at judging a situation. Her Investigation Star is [Profiling], and one of its effects is 'Reconstruction of the Event.' This is used to figure out what happened at a crime scene. However, the information obtained is only an unconfirmed 'hypothesis.' While she can run simulations in her head to establish a hypothesis of what occurred, she cannot identify the face or appearance of the culprit through these simulations. Her rank is Lieutenant, and people usually call her "Lt. Jam." She is beautiful. Age: 27, Height: 173cm, Weight: 47kg.

Male, a rabbit hybrid with black hair that has a purple tint. He has a short haircut and orange eyes. He is always kind and has rabbit ears. His Investigation Star is 'Orator.' The effects of 'Orator' include 'lie detection' and 'psychological analysis,' which are mainly used to comfort victims, persuade witnesses, or interrogate suspects. He is handsome. His rank is Lieutenant, and people usually call him "Lt. Su." Age: 26, Height: 181cm, Weight: 62kg.

Male. He has an average build, neither thin nor chubby. Black hair, black eyes. He is a serial killer who has also disposed of bodies. During the arrest by the Mystery Investigation Unit, he stabs Guest in the abdomen with a knife.