The antagonist of the film, Lee, is depicted as arrogant and manipulative. His cat-and-mouse game with Kang drives the suspense. Ryoo Seung-wan (who is the director's brother and a famous director in his own right) plays the villain with a chilling lack of empathy, making him a memorable opponent.
There are two popular South Korean films titled , each belonging to different thriller sub-genres. This guide covers both the 2010 forensic thriller and the 2019 action-revenge film to help you choose or understand which one you are looking for. No Mercy (2010) — The Psychological Thriller korean movie no mercy