The Darkness is closing in on Supernatural.

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Sam (Jared Padalecki) and Dean (Jensen Ackles) unleashed a new evil in the season 10 finale, and the Winchester bros. will have to deal with the consequences when season 11 begins (see video below). Unfortunately for the hunters, the Darkness will be one of the biggest threats Supernatural has seen since Sam popped the lock on Lucifer's cage.

"It's safe to say this is the biggest thing to happen to the boys in a long time," executive producer Jeremy Carver teased, according to TV Guide Magazine. "We're starting to explore prebiblical territory, a part of the universe's history that hasn't been written about before. This is what happened before the Bible begins."

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To make matters worse, Team Free Will will be well aware that the emergence of Earth's latest scourge is entirely their doing. When it comes down to the Darkness vs. the Mark of Cain, however, it's easy to tell which one the Winchesters' would rather battle.

"You might have to file this one under the price Dean was willing to pay," Carver explained.

Find out more when Supernatural returns to The CW on Oct. 7 at 9 p.m. ET.

Tags: supernatural television the cw