I think John is- was a demon. One of the things that always bugged me about the first episode was the speed at which John managed to grab both Dean and Sam from the burning house; he was upstairs when Dean made it out the lawn. Sure this can be one of those film tricks to build tension but d00d, the way he was moving (blur) was not human.

My Theory: John Winchester was a demon who decided to become a human, but you can never fully remove all aspects of your past life, thus the knowledge about the supernatural and possibly a remnant of some demonic ability. This would lead to the possibility of a child with some special ability; Dean was lucky, Sam wasn't.

I am, however, very confused about why the Demon let John live for so long, why not kill John and Dean and raise Sam in whatever image he wishes it... Unless we are going down the road of the Bible and it is all about free will - actually that wouldn't surprise me.

ETA: in 201, the Demon asks for John's life but does not take it itself, what is up with that? Why is it everytime the Demon attempts to kill John or Sam it is through a series of indirect methods. I am a bit stumped about the whole Dean thing but you know, Dean has a mouth that can bring out the murderous rage in people. Also, the Demon didn't kill Dean, just made him hurt so that he wished he would die.

Also, I refuse to believe that John is dead. I keep on expecting him to come back as a Demon.


Sleep now.