Michael C. Hall, Jennifer Carpenter, Lauren Velez

[Warning: This story contains major spoilers from Sunday's finale of Dexter. Read at your own risk!]

Deb has crossed over to the dark side.

Dexter's foul-mouthed lieutenant took a very dark turn on Sunday's finale, shooting her long-time frenemy LaGuerta (Lauren Velez) in order to protect her brother Dexter (Michael C. Hall). So what does this mean for Deb (Jennifer Carpenter)? TVGuide.com turned to showrunner Scott Buck to get the scoop on whether the Morgan siblings will be able to cover up this murder and so much more! Plus: Is Season 8 really Dexter's last? Read below!

Dexter finale: Did Dexter finally get caught?

Wow, Deb shot LaGuerta! What are the immediate ramifications of that? And how does this change Deb forever?

Scott Buck: Absolutely. There's so much of this season we've seen Deb try to cover for Dexter and lie for Dexter and gradually going down a darker and darker path. But I don't think she or Dexter ever imagined it would suddenly take this turn. We didn't want to shy away from what it means to cover up for a serial killer. We just took it as far as we possibly could. Yes, it's definitely going to affect her and Dexter in a very big way.

What was the decision behind bringing Deb to this point where she's done something she obviously immediately regretted?

Buck: It's a difficult question to ask because this just felt like such a natural story line for Deb to take once she discovered who Dexter was from that moment in the church, and to not arrest him and try to find a way to live with it. It just felt like it was inevitable that it would lead down this path.

Looking at the logistics, she shot her with her own gun. How does that change Dexter's initial plan to set LaGuerta up in a firefight against Estrada?

Buck: I think he can still implement that plan. He might have to make a few quick changes there, but this is someone who has covered up a lot and is a forensics expert and will know how to deal with this — especially if you're the forensics expert on the scene collecting the evidence and interpreting the evidence.

How does this affect Dexter and Deb's relationship next season? Is this the turning point they can't come back from?

Buck: It's definitely a turning point for the two of them and that's going to be a lot of what we explore in Season 8. This is going to have a huge effect on both of them. They're not just bonded in their complicated brother-sister relationship anymore. Now, it's imbued with this tragedy they both share.

Dexter's Michael C. Hall: Will Hannah turn Dexter in?

Will he feel guilty over what Deb has done or is he just so grateful?

Buck: I think he's going to have very complicated feelings when we come back to him this next season. I think he might feel worse for what he's done to Deb than for what happened to LaGuerta. He's killed so many people that adding one more that is outside the code so dramatically is fairly big deal to him, but I don't think anything is as important to him as his sister and the effect that he as on her.

Dexter did step outside the code to kill LaGuerta. Will he do this more? Or is he desperate to stay away from doing that?

Buck: I think that will cause him to examine exactly why he kills. He did a kill in Episode 10 that was completely outside the code that was done for love to protect Hannah. So he's willing to step outside the code; he's just doing it in a more mature way and accepting responsibility for what he does, rather than just simply blaming it on some Dark Passenger within him. The code is something that's always been very valuable to him and I don't think he's going to step away from it.

Dexter showed up at party in his kill suit. What was that representative of?

Buck: I think it was just to show how separate from the rest of the world these two are, walking through a party that they clearly did not belong to. It's also interesting that that scene was shot at the same place where the Season 1 finale was shot, where Dexter had the fantasy of walking down that exact same street and being greeted as a hero.

Will there still be suspicions about Dexter next season — things LaGuerta may have put in place in case she was killed?

Buck: At this point, we're not following that story line in a big way. Towards the end of Season 7, no one was believing anything that LaGuerta was saying about this and it looked like Dexter has effectively put that to rest.

Will anyone look into the warrants she had taken out for the GPS on Deb's and Dexter's phones?

Buck: The fact that the warrants were still on her desk meant that they had not yet been filed.

Hannah (Yvonne Strahovski) is still out there. Is there a chance we'll see her next season?

Buck: I certainly hope so.

Is Deb still in her crosshairs? Or is she more focused Dexter?

Buck: I think Dexter has far exceeded anything that Deb may have done to her, so if Hannah comes back for anyone, I think it's going to be Dexter first and Deb would just be an afterthought.

Dexter Scoop: How does Deb's admission change everything?

In that same vein, fans still wonder about Lumen (Julia Stiles) being out there. Is there ever a chance for that to be rekindled, especially since he no longer blames everything on his Dark Passenger?

Buck: Lumen's name comes up almost every season, but as of yet, we have made no plans for that character to return. I think she'll be much happier without Dexter in her life.

Are you guys going to continue to explore whether Dexter can have love in his life?

Buck: Definitely so. But I don't think you can really move past Hannah McKay. I think that was Dexter's first true love and first adult relationship and I don't think he's going to recover from that one for a while.

Will next season definitely be the final season or are there thoughts about continuing on past that?

Buck: That's a Showtime decision. I would like to have an answer just as much as you. We're moving towards a finale, but if Showtime decides to bring us back another year, we'd all be thrilled.

Do you think Dexter needs to finally pay for everything he's done, whether that means the show ends with his death or ends with him being arrested?

Buck: I think he'll pay in one way or another. This is a show about a serial killer and there's only so many ways a serial killer can be dealt with. None of those are typically happy endings.

If it is the final season, is there anything you're dying to do before the show ends?

Buck: One of the things I was really itching to do was have Deb find out, so that was such a big, fun thing to do this past season. The other thing is taking Dexter to a finale, so I can't really reveal what that might be, but there are things in Dexter's future that I'm very excited to finally be able to deal with.

You mentioned in the Showtime video you want to explore Dexter's origins next season. What can you tell us about that?

Buck: Yes, origins back to his childhood. We've heard Harry's (James Remar) version of what happened and we've seen some flashbacks, but I think we can widen the scope of that and see that Dexter had a slightly different beginning than even he imagined. I think it became a very interesting story and it's not just flashbacks, but it's how all of that impacts and affects his life as it is now. It's not just looking backwards; it's actually very much moving forward in an interesting way.

Does that mean we may see some of Dexter's old demons, facilitating the return of some familiar faces?

Buck: I'm not sure about that. That's always something that we talk about from time to time, but we're just beginning to break this upcoming season, so I'm not sure if we'll see that or not.

Is speed the new suspense on TV?

Will you still have a Big Bad of the season?

Buck: I think we'll have a very different Big Bad. Big Bad might not be the right words for it, but we'll definitely have some big guest characters this upcoming season.

Will there be a time-jump next season or are they going to be dealing with the immediate aftermath of the shooting?

Buck: Because we're still plotting out the season, we haven't made a decision on that just yet.

As you draw closer to the end, will more people suspect something's wrong with Dexter?

Buck: I don't know. Dexter is so smart about it. He handled LaGuerta better than anyone possibly could have. Ultimately, it was a very tragic way, but I think he was able to divert everyone's attention away from him at this point, so I think when we begin next season, he's in the clear.

After a solid season, how much pressure do you feel going into what could be the final year?

Buck: I don't want to let anyone down. I don't want to let myself down or our fans, the people who work on the show. We're all very excited to come back again this season and deliver something just as strong.

What did you think of the Dexter finale? Do you think Dexter could ultimately have a happy ending? Hit the comments with your thoughts!