I Saw the Devil (2010)
Kyung-chul is a dangerous psychopath who kills for pleasure. Soo-hyeon, a top-secret agent, decides to track down the murderer himself. He promises himself that he will do everything in his power to take vengeance against the killer, even if it means that he must become a monster himself.
Actor: Lee Byung-hun , Choi Min-sik , Jeon Kuk-hwan , Cheon Ho-jin , Oh San-ha
Director: Kim Jee-woon
Country: South Korea