The cannibal guy.
If you do watch it, be warned it's not particularly realistic. The amount of crazy serial killers that live in that one area is ridiculous, and some of the stuff they do is flat out impossible, to the point that (once or twice) it makes the characters look really stupid for not questioning it.
But it's all there for a reason and it works with the plot of the main character being driven insane, which is what the first season is about.