Sam is taken by the demon Azazel, who uses an ancient and dark spell on Sam. Sam is changed forever into the one thing that Winchesters hate above all other monsters; a Demon. Will Dean accept his brother, and if he does, will it be too late to save him from himself and others? AU No Slash. Rating may change. Sam is a Demon, but he's not evil. Demon!Sam Awesome!BigBrother!Dean