!!hot!! — I Saw The Devil Mongol Heleer Verified

The central theme of the film is that violence begets violence. Soo-hyun’s plan to "make the killer feel fear" fails because Kyung-chul is incapable of feeling empathy or fear in a conventional sense. By engaging in cruelty, Soo-hyun loses his humanity, illustrating the old adage: "He who fights monsters should see to it that he does not become a monster."