Considering all the "Big Bads" that Sammy and Dean Winchester have fought over the past 10 seasons of the hit CW horror show "Supernatural," the next one is likely to blow the top off their lids.

The previous archnemeses the brother-hunter duo have fought included Lucifer himself, archangels and demons, the king of hell and even Death, in the flesh, according to Entertainment Weekly. But all of those characters have had biblical origins and their fates have had some sort of history attributed to them that gave the heroes their advantages.

But now that the Darkness is out, the entity predates the Bible and was something God himself had to fight to keep locked up. But now, it is out, and after several millennia locked inside oblivion, there is obviously a bone to pick for the evil entity.

Series star Jensen Ackles sat down with EW and gave them a little insight into what it is.

"This one's interesting because it's not really a monster," Ackles told EW. "It's more of a primal force that we know nothing about. There's no lore; there's no guidebook; there's no instruction manual on how to deal with this." 

So in other words, Sammy and Dean are going into this fight blind, with no special weapons to put it down.

"As of right now we have it built as one specific entity, obviously that would be a character that we're introducing," Ackles told EW. "But whatever the reach of that character, what that character can do, we're not quite sure of."

This could of course be anything, considering all the surprises the show has featured over the years. But Ackles added a little something extra to that statement that puts the situation in a whole new perspective.

"We don't know the scope of her powers," Ackles said.

"Supernatural" returns to the CW on Oct. 7 at 9 p.m. EDT.