What We Do in the Shadows is returning for a fourth season on FX on July 12, bringing the show's four Staten Island vampires back after an explosive Season 3 finale. While the cast quickly settles into their new arcs for the season -- including Laszlo's efforts to care for the baby version of Colin Robinson while Nadja embarks on a personal mission to create her own vampire dance club -- the show's emotional bedrock quickly proves to be Nandor and his human bodyguard/best friend, Guillermo.

The relationship between the two has been one of the show's most emotionally effective (and darkly funny) subplots, and it's at the forefront of their story in the new batch of episodes. During an exclusive interview with CBR ahead of the show's return, What We Do in the Shadows' Kayvan Novak (Nandor) and Harvey Guillén (Guillermo) spoke about peeling back layers of their characters in the FX vampire comedy's fourth season and the process of filming around the now child-like Colin Robinson. The pair even pitched an episode where Nandor and Guillermo get to visit Disneyland.

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CBR: This season sees both Nandor and Guillermo getting into some more openly emotional story beats, with a touch of romance thrown in there. What was it like getting to explore these new, more open layers of the characters?

Kayvan Novak: Well, I would say that I think Nandor has been emotional from day one. He is a very emotional, neurotic guy, where he doesn't hold anything in, really. He wears his heart on his sleeve. I think this new quest to find love in a slightly different way to last season felt equally fresh and exciting to play for me. I was helped along the way by Nandor's new toy, his genie lamp, and his Djinn. The Djinn being played by such a fantastic actor [Anoop Desai] made it feel like a fresh new dynamic for [Nandor]. Because, you know, he's been leaning on Guillermo this whole time, and now to have this Djinn and Guillermo and just misusing this lamp in hilarious ways, then leaning on Guillermo to help kind of clean up the mess... it felt like a really exciting and fun thing to play for me, as an actor.

Harvey Guillén: I really like the layers that we all get to play this season. We've been playing, sprinkling in the trajectory of Guillermo, and that has been always fun and surprising because he's not where he started, and he's definitely not where he's going to be when we end. I think he's getting really confident and more aggressive towards what he wants in life. The clock is ticking, and he's not getting any younger. This season he's falling in love in his own way, with himself and with maybe another person -- really asking himself what he wants and what's important to him. Along the way, when his best friend/master/only person asks him to be his best man at his wedding, it's an honor.

Most people would be like, well, that's a shock because we thought they were gonna... They do love each other. You know, there's so much that [Nandor's] asking him to be as best man when he hasn't even found a wife. So that's saying something -- or it could be a tactic to keep Guillermo around, to not lose him for whatever reason. [This season], the level of layers everyone's going through, seeing Laszlo becoming nurturing to young Colin Robinson... Nadja going after her lifelong dream of becoming an owner of a nightclub and what that entails, and the Guide going against all she's ever known and being part of this... To see them dress differently, and their hairstyles are different and everyone is just like shedding away a new layer. So it's really fun to see. I'm just excited for the next seasons.

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What We Do In The Shadows Season 4 Nandor Guillermo 2

Now, this year had a unique attribute in the form of Colin Robinson no longer strictly being Mark Proksch but rather an unholy energy vampire child. What was that like to actually film the show with that as part of the process -- was Mark there on set?

Guillén: No, we never saw Mark. Mark stayed in LA. I saw him once in production because we [mostly] shot with the children who play his younger self, who are all really talented. And we never saw them because they had to insert that CG [Colin Robinson] face into that body later. So it was kind of weird because we didn't get to see Mark all of last season. I think he came in towards the end when he gets to be older, but it was weird to just see these two children run around with dots on their heads everywhere.

Novak: And then the wig as well, they were great. There were so many! There was also a stunt guy who actually looked like a 10-year-old boy. I can't remember his name. He was a lovely guy. Of course, no one told me that he was actually a grown man, so when I went on set and met him for the first time, I gave him the whole like, "Oh, hey, can I see some ID?" Then I think I swore, then I was like, "Oh, shit. Oh, sorry! Sorry." Then the director was like, "No, it's okay, man. You can swear... He's a grown-ass man."

What We Do In The Shadows Season 4 Nandor Guillermo 3

Now, I've got to bring up the Disneyland pictures of the two of you that the internet just loved so much. What are the odds we'll see an episode of Nandor and Guillermo actually at Disneyland?

Guillén: Wow, that Disney trip was a hit. That would be great. I mean, we are in the Disney family. It would be like, you know, those old sitcoms that always go to Disneyland, like Family Matters or with Steve Urkel. Maybe they'll do one of those where it's a night market at Disneyland. I don't know how, but that'd be cool.

Novak: We were joking around about it. We were like yeah, you could push me around in a pram and one of those isolation bubbles, like kids that are allergic to UV rays. Why couldn't Nandor be in one of those plastic bubble things and run around? "Goofy! You are my favorite, Goofy!" [I could end up in the Goofy suit]. "Guillermo, it is me. This is not Goofy."

Guillén: That's how you get protected from the sun, you're in the suit.

Novak: I am going around Disneyland as a mascot.

Catch Kayvan Novak and Harvey Guillén as Nandor and Guillermo when What We Do in the Shadows returns for Season 4, July 12 on FX.