Main •
Song Sae-byeok as Kang Pil-sung :A police detective who was abandoned by his family and is trying to unlock the secrets of his newly found powers of seeing ghosts. •
Go Joon-hee as Hong Seo-jung :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.
Supporting Twenty years ago •
Jang Hyuk-jin as Kim Nak-chun :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.
At Sangdong Police Station •
Lee Won-jong as Detective Squad Chief Yoo :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. •
Ahn Eun-jin as Choi Yeon-hee :A cute and lovable traffic cop who retains her youthful appearance. • Jeong Chan-bi as Yoo Seung-hee :Detective Yoo's daughter.
People around Seo-jung •
Gil Hae-yeon as Geum-jo :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.
People around Soo-hyeok •
Park Sang-min as Jang Choon-sub :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. • Kim Yeon-jin • Woo Seon-yool • Lee Jung-min • Park Soo-yeon • Gi Se-hyeong as Chun-seop's subordinate • Oh Yu-jin as Mi-seon :Female employee at Hanul Medical Center. •
Ryu Hye-rin as Hye-rin • Kwak Myung-hwa • Oh Jae-kyun • Shin Woo-hee • Lee Sang-in • Lee Chae-bin • Gong Jeong-hwan • Kwon Yong-sik •
Shim So-young as So-young • Jang Myung-woon • Baek Jae-woo •
Park Sung-yeon as Ji-sook • Cho Wan-gi
Cameos •
Jung Han-yong as the director of Hanul Medical Center •
Jang Hyun-sung as the doctor who treats Detective Chief Squad Yoo • Park Soon-chun as the director nun •
Lee Young-ah as Stephanie == Original soundtrack ==