So...Joe Carroll is a serial killer with a body count in the double digits, who then went on to become a dangerously manipulative cult leader. That means that technically he's worse than Charlie Manson who, when you think about it, never actually killed anyone himself. But what makes him a cut above a lot of other naughty characters on television is his level of intelligence. He's a college professor who went rogue and used his considerable intellect to further his sociopathy and need for control. Carroll is basically a criminal mastermind who is just as dangerous behind bars as he is out on the street, and somehow manages to stay about four and a half steps ahead of the police. That's pretty scary...but at the same time oh so charming. Do you see why he's such a conflicting character for audiences? While everyone can pretty much agree that he's a thoroughly despicable character, you can sort of see why he has, well, a following.