Check iTunes, Amazon Prime Video (with dub option), or the Umbrella Entertainment Blu-ray release.
First, let’s address the logistics. Unlike mainstream anime or Disney films, Korean thrillers rarely receive high-budget dubs. However, I Saw the Devil is an exception due to its cult status. The English dub is available on: I Saw The Devil English Dub
I Saw the Devil English Dub Review – A Brutal Masterpiece, Now Accessible to a Wider Audience Check iTunes, Amazon Prime Video (with dub option),
: The English dub sometimes adds lines to fill silence or match mouth movements (isochrony) where the original Korean version had no dialogue. For instance, a scene where a character is being subdued includes added English dialogue like "What the hell?" to fit the character's open-mouthed expression. Viewer Reception However, I Saw the Devil is an exception
I Saw the Devil is a cinematic masterpiece. Roger Deakins-level cinematography (though shot by Lee Mo-gae) demands your full attention. With a dub, you are not tearing your eyes away to read text every three seconds. You catch every subtle facial twitch from Lee Byung-hun—the quiver of a lip, the deadness in his eyes during the climax.
And one more warning: This film is notorious for its graphic violence. No dub—English or otherwise—can soften the blow of the Achilles tendon slash or the anchor sequence. Proceed with caution.