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.

Genres: Thriller, Horror

What to watch after I Saw the Devil

• The Chaser (2008) — Same subject: psychopath, serial killer
• A Bittersweet Life (2005) — Same subject: revenge
• Lady Vengeance (2005) — Choi Min-sik appears in both
• Thirst (2009) — Two steps away in the credits
• The Host (2006) — Two steps away in the credits
• Saw (2004) — Same feel: disturbing, gory