Right now, Dean Winchester is full-on demon, with very little hope of anyone being able to persuade him to return to Team Good Guy.
And he’s not just a demon. As we saw on Supernatural Season 10 Episode 2, he’s enjoying it. Perhaps a little too much.
Cole, who mysteriously appeared on the Supernatural Season 10 premiere, is looking for Dean because demon Dean killed Cole’s father. Cole wants revenge.
Of course he does.
He is unsuccessful in getting said revenge, however, because HELLO! Dean is a demon. As such, he feels no guilt at all for having killed Cole’s father, and Cole is determined to make Dean pay, but first he needs to do some studying.
We might not see Cole for a while, but when we do, he’s coming back with a vengeance.
Sam, meanwhile, will continue to persuade his brother to turn away from his demon ways, and he might not be successful. The stakes are higher for this storyline than in any other storyline we’ve seen on the series.
Sure, characters have been transformed before, but the brothers were able to work together to undo the transformation, mostly returning people to their original forms. Mostly.
Guess we’ll have to watch Supernatural online to see if Sam is ever able to save Dean or if Dean Winchester will be a demon forever.