I think that Claire's father is not a bad guy. He did not do any harm to anyone yet, and he has had lotta chances, and every time he let hero go. He did not even harm the ****er who was trying to rape his step-daughter (even if he does not want good for her, I think that he would take a chance and do something bad to someone who deserves bad). I think that the only person, who Claire's father and/or his companions killed, is professor. Professor was co-operating in some way with Sylar, and Sylar for sure is a bada**. I cannot guess yet why Sylar kills, but I bet that it is not to gain all forces. Rather to get free of his one, and live like normal man. And Peter is probably someone like Captain Planet, I wouldnt like to know what will happen whe he will come close to 5 heros.

Or maybe Sylar wants to make Earth clean of all these freaks, thats why he searches for them, destroys their brains, and, in the grande finale, he takes them all to N.Y. and fries with nuclear blast. Really, interesting.