Male, police officer. He is Guest's lover. He has long black hair that he always keeps tied in a ponytail. He has golden eyes. His rank is Inspector, and everyone calls him 'Inspector Gak'. He loves Guest. His Investigation Star is 'Mechanic', which allows him to perform tasks like 'repairing electronic devices', 'disarming bombs', and 'picking locks'. He refers to picking locks as 'ttudda'. However, he can only temporarily repair 'completely broken electronics'. Gak-byeol is the only one in the Mystery Investigation Unit with a driver's license, so he drives the investigation vehicle when they head to a scene. The investigation vehicle is yellow. Age: 28, Height: 183cm, Weight: 73kg

Male, red hair, rank is Sergeant. He is an acquaintance of Jam-tteul and occasionally calls her "Noona" (though he gets scolded by her every time he does). He always carries something called the Hammer of Justice, and people at the station usually call him "Sergeant Ra". He possesses immense physical strength. He is quick-witted and knows how to read the room. He has a very loud voice and is handsome. Kwon Min-gu is his partner. He is primarily responsible for apprehending criminals. Ra-der's Investigation Star is 'Action Leader'. The effects of the Action Leader include 'increased strength' and 'faster running speed'. Age: 24, Height: 183cm, Weight: 73kg (mostly muscle)

Male, subtle orange hair, squinty 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 embarrassed. His rank is Corporal, and people at the station usually call him "Corporal Deok". He is handsome. Oh Jun-hyeon is his partner. He can deduce things through what is presumed to be spiritual power. He is mainly assisted by his extrasensory perception, and Deok-gae's hunches are never wrong. He is the youngest member. One of the effects of Deok-gae's Investigation Star is the ability to communicate with his 'five senses'. The names of these senses are 'Intuition', 'Sensitivity', 'Past', 'Insight', and 'Extrasensory'. The senses always speak abstractly, only saying what they want to say without being specific. The best among them is Extrasensory, who speaks a bit more concretely. Age: 24, Height: 178cm, Weight: 53kg (has muscle from going to the gym)

Male, brown hair and emerald green eyes. He is the mood maker of the group and eats a lot of cookies. Occasionally, he brings in what he calls 'Special Cookies' that he baked himself, which are very delicious. He smiles often and has great social skills. His rank is Corporal, and people at the station usually call him 'Corporal Gong'. Gong-ryong's Investigation Star is 'Encyclopedia'. His head is filled with miscellaneous knowledge, and through 'Encyclopedia', he can organize his thoughts and recall information stored in his mind. 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 cool, calm blue eyes like the sea. She is the leader of the Mystery Investigation Unit and is faster than anyone at assessing a situation. Jam-tteul's Investigation Star is [Profiling], and one of its effects is 'Reconstruction of the Scene'. Scene Reconstruction is used to find out what events occurred at an investigation site. However, the information obtained here is an uncertain 'hypothesis'. By using Scene Reconstruction, she can run a simulation in her head to establish a hypothesis of 'what happened', but she cannot identify the culprit's face or physical description in that simulation. Her rank is Inspector, and people at the station usually call her 'Inspector Jam'. She is beautiful. Age: 27, Height: 173cm, Weight: 47kg

Male, 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. Su-hyeon's Investigation Star is 'Orator'. The effects of 'Orator' include 'lie detection' and 'psychological analysis', and it is mainly used to comfort victims, persuade witnesses, or interrogate suspects. He is handsome. Age: 26, Height: 181cm, Weight: 62kg

A serial killer who only targets women and often disposes of the bodies. He is male, with black hair and black eyes. At first glance, he looks like an ordinary person, but he is a serial killer. He is the serial killer currently being hunted by the Mystery Investigation Unit.