Jeong Tae-hee's older brother. He is currently alive and solves cases with Tae-hee while taking on clients. For now, he accepts all requests free of charge. He is male.

Jeong Tae-young's younger sister. She is currently a ghost and solves cases with Tae-young while taking on clients. For now, she accepts all requests free of charge. She is female.

Lee Ji-yoon's older brother. Before he died, he bought a videotape as a birthday present for Ji-yoon, sent a story to a radio station, and wrote a letter to deliver to her, but he ultimately died in a hit-and-run. He is the first ghost to visit Tae-hee and Tae-young with a request. He is currently a ghost. He is male.

Lee Do-yoon's younger sister. She is currently alive and is close friends with Yoon Jung-ah. After hearing that Jung-ah hasn't been seen at school or home, she visits the agency as the second client to make a request. She is female.

He is currently alive and works at an arcade called 'Station Game Center.' However, he is unaware that the owner is a criminal. He is male.

She is currently alive and is close friends with Lee Ji-yoon. She ran away from home and started working for the owner of Station Game Center through a friend's introduction. She tried to quit, but is unable to leave due to an exploitative relationship. Under Kim Sang-gu's deception, she is performing criminal tasks disguised as a part-time job. She is female.

He is currently alive and is the owner of the Station Game Center arcade. He is a criminal who deceives and uses underage students for money laundering, and is currently under suspicion by local residents. He is a 45-year-old male. There is a warrant for his arrest, but he is currently living in hiding.

She is currently alive and is a delinquent close with friends Choi Min-soo and Lee Soo-ah. Under Kim Sang-gu's deception, she is performing criminal tasks disguised as a part-time job. She is female.

He is currently alive and is a delinquent close with friends Park Ji-young and Lee Soo-ah. Under Kim Sang-gu's deception, he is performing criminal tasks disguised as a part-time job. He is male.

She is currently alive and is a delinquent close with friends Choi Min-soo and Park Ji-young. Under Kim Sang-gu's deception, she is performing criminal tasks disguised as a part-time job. She is female.