Supernatural is just days away from the start of filming for season 10, and viewers should prepare themselves for a rather terrifying Dean when the series returns.

'Supernatural' Director Jensen Ackles Pranked [PHOTO], Series Not Filming Premiere First

Now deceased, the elder Winchester brother has received a pair of shiny black eyes courtesy of the Mark of Cain (see video below). As the Demon Dean (Jensen Ackles) storyline moves forward, one Supernatural writer has warned fans that the character is about to experience a major shift in personality.

"I can't wait to see Jensen kill it as demon Dean," tweeted writer Jon Bring on Tuesday. "He's gonna be one scary sonofab---h (sic)."

Sam & Cas Prepared To Kill Demon Dean On 'Supernatural', Jared Padalecki Talks Containment Options

Meanwhile, Ackles has also weighed in on Dean's future and the actor pointed out that having the Mark of Cain could make him far more powerful than your average demon.

"It's interesting because there are a few aspects to what could potentially be Demon Dean," Ackles explained at Rome's fifth annual Jus In Bello Con. "You've got to think about the fact that he's got the Mark of Cain as well. So you look back at what that was for Cain and the power that he had against other demons. So is Dean going to be this ultra-powerful demon, and therefore be ultra bad? I don't know. I will say that I'm looking forward to exploring what that means and where that's going to take the story."

Ackles is currently also directing the third episode of season 10, which will also be the first episode to film next week.

Supernatural will return to The CW on Oct. 7 at 9 p.m. ET.