The Kid Is A Psychopath
Spoilers Ahead
In this movie there is not one character that is likeable. In particular the main child Seth has the traits of a psychopath. He sees his friend being kidnapped by the car creeps and tell no one about it. He can relate to the corpse of a baby and has conversations with it. Later on the "vampire" woman gets into the same car of killers and he doesn't warn her.
I imagine it would be too late now but if they did make a sequel they could show how he grew up into a serial killer.