The parents
I'm an hour into this movie and I think I am still watching just to see how the parents die. They are so obnoxious. The stupid, doormat wife just repeats everything the husband says. Neither of them ever believe their kids. The whole family has bizarre trust issues. The dad needs medication because he is quite possibly one of the most paranoid, uptight father character I've ever seen (the only one worse is the neighbor, closeted, military dad in American Beauty).
I really hope their deaths are bloody but I'm sure I'm going to be disappointed.