Main

• Son Hyun-joo as Kang Ki-hyung

The team leader and a veteran NCI profiler who has published a book on criminology. Despite his aloof and expressionless exterior he cares deeply for his team, whom he considers to be his second family.^[6] He and his wife Seo Hye-won have a son named Han-byul. He is the equivalent of Aaron Hotchner, portrayed by Thomas Gibson.

• Lee Joon-gi as Kim Hyun-joon
  • Kang Yi-seok as teenaged Hyun-joon

A second-generation police officer, joins the NCI at the recommendation of Kang Ki-hyung.^[6] He was initially a SWAT officer specializing in EOD who had transferred to the Violent Crimes Unit as an investigator after watching one of his subordinates die, when a bomb their team was defusing, exploded. He witnessed his father being murdered by a suspect when he was a child and has little sympathy for criminals.^[7] His brash nature and temperament has put him at odds with Ki-hyung and Sun-woo at times but he quickly proves his worth with his attention to detail, sharp instincts and accurate profiling skills.^[8] He is the equivalent of Derek Morgan, portrayed by Shemar Moore.

• Moon Chae-won as Ha Sun-woo
  • Jeong Ye-in as teenaged Sun-woo

An NCI agent and behavior analyst, her gruff demeanor and exacting mannerisms cause some friction between her and Hyun-joon. She tends to follow protocol and goes by the book, in contrast to Hyun-joon, who tends to rely on his instincts and experience. It is eventually revealed that it is her way of coping with the horrors she regularly witnesses on the job. Like Hyun-joon she is a former police officer. She was only hired to fulfill the female quota and relegated to desk jobs and running errands, which she said spurred her to work even harder to get to where she is now.^[6] Her father is a well-known defense lawyer whose clients include members of the business and political elite but Sun-woo remains estranged from him due to the fact that he has bailed out some of the very people she arrested. She is the equivalent of Emily Prentiss, portrayed by Paget Brewster.

• Yoo Sun as Nana Hwang

She is the NCI's bubbly technical analyst who provides support from her computer. She is the equivalent of Penelope Garcia, portrayed by Kirsten Vangsness.

• Lee Sun-bin as Yoo Min-young

She is the NCI's media liaison officer and handles press conferences.^[9] She has been the guardian of her orphaned niece Ha-eun since the deaths of her sister and brother-in-law. She is the equivalent of Jennifer "JJ" Jareau, portrayed by A.J Cook.

• Go Yoon as Lee Han

The resident genius and holder of two doctorate degrees, he is a profiler who often follows the team to the field to analyze the crime scene or the suspect's house for further clues. He is socially awkward and has a tendency to spout encyclopedic facts at the wrong time. He is the equivalent of Spencer Reid Ph.D., portrayed by Matthew Gray Gubler.

Supporting

• Kim Yeong-cheol as Baek San

He is Kang Ki-hyung's superior and has generally been supportive of him and his team. He is the equivalent of Erin Strauss, portrayed by Jayne Atkinson. Kim was busy filming My Father is Strange back and forth so he only made a few appearances.

• Kim Do-yeon as Yoon-ah's mother
• Kim Kang-hoon as Kang Han-byul, Kang Ki-hyung's son
• Im Soo-hyang as Song Yoo-Kyung. (ep. 6-7)
• NewSun as Choi Na-young, Sang-hyun's younger sister. (ep. 1-2)
• Oh Yeon-soo as Seo Hye-won, Ki-hyung's wife. (ep. 1-4)
• Sung Chan as Choi Sang-hyun, Hyun-joon's best friend and a SWAT agent. (ep. 1)
• Kim Won-hae as Kim Yong-cheol, the serial killer also known as The Reaper.^[10][11]
• Hwang Bo-mi as reporter
• Park Geun-hyung as Commissioner General Kwon Sang Ho
• Park Han-sol as Son Na-kyung
• Shin Da-won
• Park Si-eun^[12] as Mo Ji-Eun
• Hong Ji-yoon as Park In Hye
• Kwon So-hyun as Kwon Yoo Jin (cameo)
• Changjo (cameo)

Part 1

Part 2