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A woman who can see ghosts, read people's minds, and control people, plus has some knowledge about spirits. She has never met her mother, having been abandoned by her at a young age.
The new body that Hwang Dae-du possesses. He is a wealthy businessman and is the CEO of TF Group. When possessed, he could control a drug that can turn people into a zombie-like creature.
A follower of the serial killer Hwang Dae-du who briefly inhibits his spirit. He is a surgeon at Hanul Medical Center. He is killed after he is shot multiple times by policemen.
A former police officer and veteran detective who lost his partner and is killed by Seon Yang-woo. He arrested Hwang Dae-du. He wages constant battle with Hwang Dae-du and will do anything to stop him from getting power.
Seo Eun-woo as Kim Ji-hang
Detective Kim Nak-chun's daughter
Won Hyun-joon as Hwang Dae-du
A serial killer responsible for 30 murders over 5 years. He is a spirit, having been executed 20 years ago, but seeks to gain power to restore his body.
The chief of police who acts as a Guardian to Kang Pil-sung. He is a tough but soft officer who tries to help his comrades. He is killed when he is shot but goes into Pil-sung to instruct him what to do.
Park Jin-woo as Choi Nam-hyun
A police officer who is Kim Joon-hyung's boss. He gets discouraged easily.
Kwon Hyuk-hyun as Kim Joon-hyung
A new recruit who is Choi Nam-hyun's partner. The youngest detective.
Seo-jung's mother, she is a worshipper who was killed by Seon Yang-woo. Her spirit is then killed by Hwang Dae-du. She had the power of summoning spirits but unlike her daughter, she can cast spells.
Jo Won-ki as Bae Do-ryeong
A playful shaman who enjoys dating pretty women who comes to him for fortune telling.
Lee Ji-hae as Cho Seung-kyung
Seo-jung's landlady and sports dance instructor. She is in love with Bae Do-ryeong.
Gangster boss who takes care of Oh Soo-hyeok's work and takes advantage of other people. Soo-hyeok's assistant who becomes the new Hwang Dae-du when his spirit enters his body. He was responsible for killing Pil-sung's mother and his assistant.
Others
Jeong Hae-na as Sohee
Seo-jung's best friend and owner of a clothing store.
This drama airs on a cable channel/pay TV which normally has a relatively smaller audience compared to free-to-air TV/public broadcasters (KBS, SBS, MBC and EBS).
남궁민 "'김과장'에 빙의 된지 오래..종영 아쉽다" 소감 [Namgoong Min "It's been a long time since I've been possessed by 'Chief Kim'... I'm sorry it ended"]. Sports Today (in Korean). 2017-03-30. Retrieved 2022-12-20.
Promotional poster