'Supernatural' Season 8: Finale Preview, Castiel's Choice, United Winchesters And More From Jeremy Carver

Three episodes remain in Season 8 of "Supernatural," and as we approach the finale, Sam (Jared Padalecki) and Dean (Jensen Ackles) will meet Metatron (Curtis Armstrong), face the final trial and, presumably, be caught in a showdown with Crowley (Mark Sheppard), Naomi (Amanda Tapping), or both. All in a day's work for our long-suffering Winchesters.

To preview the last three episodes, The Huffington Post spoke with showrunner Jeremy Carver about the last trial, Naomi's plans, Castiel's (Misha Collins) dilemma and how traumatic the "Supernatural" Season 8 finale will be. Check out what he had to say below.

The first two trials were very physical for Sam. Will the third be more mental or emotional instead?
I think it’s a mix of a little bit of everything. Yeah, I think what Sam is experiencing from here on out is a mix of everything this season has led him to. It’s a combination of everything you just hinted at.

Can you say anything in terms of how he's being changed internally by the trials? It's been hinted at so far, but not delved into.
I’d love to, but I can’t. [Laughs.] That’s something we definitely delve into in the next several episodes, so it’s not that we won’t, I just can’t now.

In theory, Sam has to complete the trials solo, so can you say anything about what Dean will be up to during the final test?
Well, these boys are both very much completing these trials together. It might be Sam who’s doing the actual act, but it’s very much a team effort that is necessary to do these things. I know Sam was a little more solo when he had to go down to Purgatory, but it’s a team effort. Rest assured that Dean will very much have his hands full.

We know that Dean's storyline has always been more closely linked with the angels and his role as Michael's vessel, while Sam's has been more linked with demons and his tie with Lucifer. Is any of that going to come into play for Dean in terms of the angel tablet?
I can’t say too much about the plans in terms of the angel tablet. I can say it won’t be directly related to this notion of Michael. It’s part of a conversation, but it’s not the driving part. It’s part of our mythology so it’s always there.

Castiel has been very displaced and in a constant state of change this year. What can you reveal about his arc in the final run of episodes?
I can say that Cas plays into this final run of things in a very big way. The last we saw him, he had very much become a protector of this tablet. I think Cas is going to have a few very, very big choices to make in this last run of episodes in terms of -- how do I say this? -- what kind of angel he wants to be and what kind of Heaven he wants to be part of.

Did his rebellion against Naomi break the last of her control over him, or is her brainwashing a lingering problem for him?
That’s a lingering thing, as is the character of Naomi herself in terms of what she’s really all about and what she’s up to. That’s something that we explore in this final run as well.

Obviously, she helped the boys out with freeing Bobby's soul from Crowley, and made her best pitch to Dean in terms of how helpful she is, so can we expect an "enemy of my enemy is my friend" kind of situation with the Winchesters against Crowley?
You’re fishing in the right pond there. I think [Naomi's] intentions and her motivations have been intentionally opaque in terms of what she’s really after. I think folks are going to be surprised up to the last minute in terms of how really to think about Naomi and what she really wants.

The Men of Letters aspect of the storyline has been a great new addition to the mythology. How will that play into the last batch of episodes?
I can say that the Men of Letters is probably one of the most fun new elements of the show that we introduced this year in terms of offering not only another window into the boys' past -- and certainly is something that I think Sam more so at first and now even Dean has sort of embraced as a part of their legacy -- but it’s also just opened up a tremendous number of story options for us. So, we’ll get a taste in this last run of how being part of this legacy will influence how they look at certain cases and aspects of cases and the new resources in front of them.

Are the brothers a united front in the last couple of episodes? That balance has shifted on and off all season in terms of being on the same page, but will they have some equilibrium as we reach the finale?
I think you could say that at the beginning of the season, the one thing that was really holding these two together when they were coming from such separate places was this shared sense of revenge. As we head into this final run here, they’re going to be presented with a series of challenges and obstacles that will basically make them question just how far they’re willing to go to seek this revenge. That influences everything from how united they are, etcetera, etcetera. I’m trying to think of an artful way of saying this ... I’ll use a Mike Tyson quote. I’m paraphrasing Mike Tyson when I talk about the boys being united: It’s like everybody has a plan until they’re hit. So, the best-laid plans can go out the window when a counter-attack happens.

The finale's title is "Sacrifice," which is fairly ominous. Are you willing to hint anything about the nature of that sacrifice?
Only in what I said before: This questioning of how far are you willing to go to get what you want. That’s about as far as I can go.

I know you started out this season with the goal of bringing the brothers to a more mature and healthy relationship. Do you think you've accomplished that, or is there more work to be done between them next season, as far as you're concerned?
I think it’s always an ongoing process. I hope that we've reached that point already in the way they talk to each other and such. It’s sort of bringing the boys there and then maintaining that level of maturity. To be completely frank, they’re brothers, so they wouldn’t be brothers if they didn’t occasionally slip into great levels of immaturity ... Each brother came in with this new-found sense of self. It was a chore getting the other brother to understand that they had changed in some ways and that needed to be respected. They might not have been happy about it, but if you love somebody, then you accept their changes as well.

The introduction of the Men of Letters storyline did a good job of luring Sam back into the hunting life and giving him an emotional tie to the family business, discovering he was from a legacy of nerds, in a way. Would you say he's now firmly rooted in hunting again, or does he still have one eye on the door and a regular life in the back of his mind?
Well, I’ll quote someone else random: Every man is the same man he was when he was 14. I don’t know that your insecurities or your wishes or your hopes ever truly go away. I think you adjust life expectations and such. I don’t think you can ever say never to Sam. I think he’s more firmly rooted in the hunting life and what he needs to do to secure his place in this hunting family more than ever. But as to the future, from a storytelling perspective, it’s always open. You never know what’s going to happen.

Dean seems, at least to me, like he's evolved so much in terms of being able to have honest, vulnerable conversations, which we've seen with Sam and Castiel and Benny and Charlie this season. Was that one of your goals this year, fleshing out that aspect of him and opening him up a bit more?
Yes. It was a shared set of circumstances that made his friendship with Benny, I think, so rich. Him and Castiel have just been so close for so long, and likewise with Sam. So if that’s been brought out more, I think that’s great. We started out very much on that course in the beginning of the season. The short answer to your question is yes. But to me, it’s more a testament to the folks he surrounded himself with.

What can you preview for the season finale? Will it traumatize the fanbase, as usual?
[Laughs.] I can only say that by the end of the finale, the fans can come to expect a brand new world. Things are a'changing. So, I’ll skip the trauma part and just say there’s lots of changes afoot.

"Supernatural" airs Wednesdays at 9 p.m. ET on The CW.

What do you think the finale's title, "Sacrifice," is referring to? Share your predictions below!