Thus, keep these caveats in mind when I opine that I Saw The Devil is a gratuitous abattoir of a film that is pornographic in its excessive violence, and seems to have little objective beyond inducing nausea in its viewers.
The movie is essentially a grudge match between serial killer Kyung-chul (Chio Min-sik) and police cop-gone-obsessive-vigilante (Lee Byung-hun), with the latter jettisoning any sense of impartiality and justice after the brutal murder of his fiancĂ