I Saw the Devil - Characters & Cast

Initially motivated by a desire to avenge his fiancée, but his drive evolves into an obsessive need to exert absolute power over a man who knows no fear.

Starts as a disciplined NIS agent and transitions into a merciless vigilante. By the end, he has lost his job, his family, and his moral compass, finishing the film as a broken man crying in the street.

Driven by predatory instincts and a total lack of empathy; he kills and rapes simply because he can, finding amusement in the 'game' Soo-hyun plays with him.

Kyung-chul does not experience a traditional character arc; he remains a static force of pure psychopathy. He 'wins' by breaking Soo-hyun's spirit, proving that even in death, he could corrupt a good man.

Wants justice for his daughter but is caught between his professional ethics and the visceral desire for her killer's suffering.

A retired police officer who understands the darkness of the criminal world. He tries to warn Soo-hyun of the cost of revenge but eventually becomes a victim of the very cycle he feared.