“Supernatural” returns to Wednesday nights at 9 p.m. as of March 18, and Variety recently caught up with Jared Padalecki to find out what’s ahead for the hit CW drama in the remaining episodes of season 10. When we last saw the Winchesters, Dean (Jensen Ackles) had just killed Cain (Timothy Omundson), but failed to remove the murderous Mark that Adam and Eve’s firstborn son transferred to him last season, leaving Sam (Padalecki) and Castiel (Misha Collins) concerned about his mental state.

While Dean managed to retain his humanity while facing off with the bloodthirsty Knight of Hell, both brothers know that the Mark of Cain remains a threat to Dean and everyone around him, and Padalecki told Variety that Sam will do whatever it takes to help free the elder Winchester from the curse.

“Sam knows his brother very well, and he knew when he saw Dean’s face after Dean had gotten rid of Cain — but still had the Mark — that Dean was not okay. He knows Dean is too gruff and tough to admit all the time he needs help, though he has, here and there, finally broken down and said, “Yeah, I could use a hand.” So Sam is going to do what he thinks is best for his brother,” Padalecki previewed. “Sam’s been down in dark places, and Dean has always helped him through, so I know, selfishly, Sam doesn’t want to lose his brother, but unselfishly, Sam would like to help his brother the same way that his brother’s helped him many times.”

According to Padalecki, that will prompt Sam to “keep researching behind Dean’s back a little bit and calling on help from Castiel and from Charlie [Felicia Day], which is fun. Sam’s going to try to keep moving his feet and not just ignore what he knows his brother is going through.”

During their brutal showdown, Cain predicted that Dean will end up killing Sam, just as Cain murdered his own brother, Abel — a prophecy that Dean declined to share with his sibling. “Sam’s keeping secrets from Dean, but Dean’s also keeping some secrets from Sam, and Cain being a demon of sorts, Dean is trying to pawn it off like ‘demons lie and you just said that to get under my skin.’ So I think Dean is trying to ignore it, but of course, it’s swirling around somewhere in the back of his brain,” Padalecki previewed. “Sam — not having the knowledge of what Cain had said — is going to keep on just doing what he’s doing while Dean obviously struggles with the fact that this ancient Biblical character told him that they were doomed for some destiny.”

The Winchesters have faced everything from ghosts to Lucifer himself, but Padalecki believes that in some ways, the so-called “big bad” of season 10 is actually “the bad within themselves; for Dean, it was the Mark of Cain. The big bad is sort of a seemingly inanimate object on his forearm.”

Still, that doesn’t mean that the Winchesters won’t be battling external threats in the run up to the finale. “As far as a character… we thought getting rid of Cain would get rid of the Mark and that didn’t work, so [we’re] on to the next thing. We think we come up with another way to possibly remove the Mark of Cain from Dean’s arm, but it involves us running into several big bads that are all in cahoots with each other who are trying to thwart our goals, and we see that very, very soon,” Padalecki teased.

Another looming threat is the long-lost mother of Crowley (Mark Sheppard), Rowena (Ruth Connell), who has been slowly but surely worming her way into a position of power within the King of Hell’s regime. Padalecki posits that she may prove to be an even greater threat to the Winchesters than the metaphorical devil they know.

“Rowena has clearly, like Crowley, mastered the art of manipulation,” he pointed out. “So I think she might even be more dangerous. We know Crowley’s bad, we have a history with him. We’ve known him for five seasons; we’ve seen his good, we’ve seen his bad. With Rowena, she’s just dangerous enough. She’s almost like Ruby in season four, where it’s like, ‘I haven’t seen you do the bad that I’ve seen Crowley do, so I’m more likely to trust you,’ and once you trust somebody like that, you’re opening yourself up for a lot of problems.”