Supernatural's Dean Winchester is taking a trip to the dark side.

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Throughout season 9, Dean (Jensen Ackles) has been slowly falling under the dark sway of the Mark of Cain and the First Blade as Team Free Will pursued Abaddon (Alaina Huffman). Now that the self-styled Queen of Hell has been permanently dealt with, Dean should allow the power of the Mark subside.

However, his reluctance to part with the Blade at the end of "King of the Damned" and his determination to bring it with him during "Stairway to Heaven" seems to indicate otherwise (see video below). If this is the case, viewers can expect Dean's recent symptoms to intensify through the finale.

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"I think Dean's becoming less compassionate. He's becoming a little bit more primal in his dealings with good and bad," Ackles explained, according to Entertainment Weekly. "He's becoming a little bit more tunnel vision, and he's getting really really amped up very quickly. You might want to say it's almost like Dean's putting on blinders and taking steroids. So it's a dangerous combo."

Will Dean, Sam (Jared Padalecki) and Cas (Misha Collins) be able to quell the Mark's influence before the summer hiatus? A recent tweet from first assistant director Kevin Parks indicates that Cain's brand will play a major role in the season's final episodes.

"Jensen did a great job being taken over by the power of the blade. You will just have to watch the last 2 episodes to see what happens!" Parks teased.

Find out more when Supernatural airs Tuesdays at 9 p.m. ET on The CW. Click the video below to see a preview of the series' next episode, "Stairway to Heaven."