10 Horror Movies Where Evil Wins

4. I Saw The Devil

There's a saying that goes; "the only thing necessary for the triumph of evil is for good men to do nothing". In the case of Kim Jee-woon's 2001 masterpiece of brutality though, the only thing necessary for the triumph of evil was for a good man to enjoy what he was doing a little bit too much.

After Kim Soo-hyun's fiance is mutilated and murdered by serial killer Kyung-chul, the secret service agent tracks down, stalks, and begins to gradually torture his target in an effort to exact retribution. He knows his every move and routinely appears out of nowhere to save his next victim and gravely wound him in the process.

But he enjoys it too much, and after Kyung-chul overhears crucial information about Kim Soo-hyun's plan, he tracks down his father and his sister and kills and disfigures them respectively. This triggers the endgame, and although Soo-hyun enacts the ultimate punishment by having Kyung-chul's own family walk in on him right as he's decapitated by his own guillotine, he suffers a total mental breakdown in the process.

Having turned down several opportunities to bring him to justice, his own evil eventually won out. By the time he realised this, it was too late.