Supernatural's Dean Winchester took a turn towards the dark side during the season 9 finale, but that doesn't mean his humanity is gone for good.]

'Supernatural' Writers Tease Early Season 10 Episodes & Winchester Brothers' Relationship

Crowley (Mark Sheppard) and the Mark of Cain pulled Dean (Jensen Ackles) back from the total darkness of death during "Do You Believe in Miracles," and left him to look through the darkened eyes of a demon instead. Considering Dean railed against becoming one of Crowley's minions during season 3, it's safe to say he and Sammy (Jared Padalecki) will be looking for a cure by time season 10 rolls around.

There is one known way to cure a demon, but using it could come at a high price for Sam. The younger Winchester brother proved during "Sacrifice" that he could use the Men of Letter's formula to cure even Crowley, but doing so would result in his own untimely death. Unless, of course, Gadreel's (Tahmoh Penikett) healing removed any repercussions of the Trails from Sam's system.

Jensen Ackles Believes Demon Dean Will Retain Human Aspects of Dean, Explains New Demon Challenge

"There is a possible way, which might be the way that ultimately Sam saves Dean," Ackles stated at Rome's fifth annual Jus In Bello Con. "I don't know that there's another way that we've introduced on the show. Granted, there might be another way. He might get Crowley to talk, he might get another demon to talk or maybe Castiel's got some new-found power with Metatron and his situation. I don't know. There are question marks there about what's going to happen, but there is definitely an option on the table."

However, Dean's Mark of Cain may complicate matters even further.

"I don't know if it will work because then again...Dean is probably going to be a little bit more powerful than a regular demon with the Mark of Cain so I don't know how that locks the demon in even more or what," Ackles explained. "These are all questions that I have as well so I'll be interested to see how the writers play it out."

Find out more when Supernatural returns to The CW this fall.

Tags: supernatural the cw television