'Supernatural' Season 10 Sees Sam and Dean's Grandfather in Flashback

The television series "Supernatural" is scheduled for a Season 10 premiere on Oct. 7 and will be picking up from where season 9 left off. Dean Winchester will become a demon.

Season 10 might be seeing the conflict between Sam and Crowley. Dean's demon transformation was not apparent to Sam at first but has realized that it was Crowley's fault and not Dean's. At this point, Sam got mad at Crowley and not at his brother Dean.

"He doesn't know that he's a demon at the beginning of Season 10. But when he finds out his brother isn't just missing, he's a demon, it doesn't piss him off. He doesn't think Dean did it on purpose or anything. He gets pissed off at Crowley instead," Padalecki told E! Online.

Dean's demon transformation was brought about by the Mark of Cain. This was after he was fatally wounded during his fight against the angel Metatron. He promptly dies from his wounds and Sam attempts to summon Crowley to make a deal to resurrect him.

It would seem that Crowley has already visited Dean and reveals that the Mark of Cain won't let go of him, hence his transformation into a demon.

Also it would seem that another Winchester will be making an appearance in the tenth season. Gil McKinney, who plays as Sam and Dean's grandfather Henry Winchester, is going to appear during a flashback.

The grandfather Winchester first appeared in season 8 in an episode where he was shown to have died while fighting against the Knight of Hell. He was revealed as a member of the Men of Letters afterwards.