I Saw the Devil is a 2010 South Korean action thriller film directed by Kim Jee-Woon and written by Park Hoon-Jung. Starring Lee Byung-hun and Choi Min-Sik, the film follows NIS agent Kim Soo-Hyun (Lee), who embarks on a quest for revenge when his fiancée is brutally murdered by the psychopathic serial killer Jang Kyung-Chul (Choi). I Saw the Devil made its premiere in the United States at the 2011 Sundance Film Festival and had a limited U.S theatrical release.
I Saw the Devil was Choi Min-Sik's first major role since the changes to the Korean screen quota system.
Kyung-Chul (Choi Min-Sik) is a dangerous psychopath who kills for pleasure. He has committed infernal serial murders in diabolic ways that one cannot even imagine and his victims range from young women to even children. The police have chased him for a long time but were unable to catch him. One day, Joo-Yeon, daughter of a retired police chief becomes his prey and is found dead in a horrific state. Her fiance Soo-Hyun (Lee Byung-hun), a top-secret agent, decides to track down the murderer himself. He promises himself that he will do everything in his power to take bloody vengeance against the killer, even if it means that he must become a monster himself to get this monstrous and inhumane killer.
Saw the Devil was released in South Korea on August 12, 2010. The film premiered at the 2011 Sundance Film Festival on 21 January 2011. It also received screenings at several other international film festivals, including the Fantasporto Film Festival, Toronto International Film Festival, Sitges Film Festival, San Sebastian Film Festival, and the London Korean Film Festival.
North American distribution rights were acquired by Magnet Releasing which released it on a limited basis on March 4, 2011. Optimum Releasing distributed the film in the United Kingdom.