Claude Frollo

he's a sick sick bastard, even from the movie's start! Kills an innocent woman, tries to drown her baby but ends up keeping him locked up in a tower (while psychologically manipulating him for 20+ years), lusts after Esmeralda saying that she'll either 'be his or be burnt at the stake' ... and the whole time, he thinks he's in the right, being a good Christian.
And then he gets one of the best song sequences EVER. 'Hellfire' is HAUNTING.