Harvey Guillen Says to Expect the Unexpected with Final Season of 'What We Do In the Shadows' (Exclusive)

The 33-year-old actor really broke out big thanks to his role on the FX comedy, a spinoff from the 2014 film of the same name. On the show, he plays the familiar -- or put-upon human companion/errand boy -- to a vampire in a house full of them. Over the show's five seasons, he's longed to be turned into a blood-sucker himself, while also grappling with the fact he's a descendant of legendary vampire hunters, the Van Helsings.

The most recent season showed him start to turn into a creature of the night, only for him to realize he doesn't quite have the stomach for it and revert back to his human form. That, says Guillen, sets up an interesting dynamic for the sixth and final season.

"Well, sometimes we think we want something for ourselves and we think that will fix everything. That lives will be fixed because of this one thing that we get or a tangible thing that we own or a career that we have. And half of the time, that's not true," he said of Guillermo's journey.

"I think that true happiness has to be found within you first. And it doesn’t matter where you're at, who you're with, it has to be with you first. You have to be happy with yourself first," he continued. "I think he overshot the idea of this world that he wanted to be a part of. Ironically, for all these years, he captured and killed so many virgins for his master, he's not a natural-born killer."

Guillen teased that Guillermo will "go on a path we didn't expect" in the coming episodes, saying the character's "wish might have shifted" a bit since the events of last season. "And it might be the best thing for him," he added.

He went on to call the final season "the perfect cherry on top that people do not expect," saying it will leave viewers exclaiming, "What?!" and "Whoa, did not expect that!" Guillen himself is really "excited" for fans to see it, as they're already more than halfway done filming their last episodes. While they're so far along, he also said the reality of the show's ending hasn't quite set in yet.

"It hasn't really hit us yet. We're all just hanging out like it's regular. I was with [costar Kayvan Novak] the other day and he was just like, 'Oh man, this reminds me of the pilot.' We were doing a scene, and he said one of the lines from the pilot, and I was like, 'Can you believe that was six years ago?'" he explained. "I think it hasn't hit us completely yet. Talk to me later in the year and see where we're at."

"It's so weird because we've been doing this now for six years. And that's half a decade of our lives into a show that has meant so much to so many people. It meant so much to us, it has changed our lives," he continued. "It has been something that hasn't been done before on television, and the critics love it. People are like, 'Why is it ending?' Well, if you think about it, six years is a long time. And you'd rather exit on a high note than be the show that people go, 'Is this still on?' And I think we accomplished that."

As for what's next, Guillen is staying booked and busy. In addition to the just-released Wish and The Thundermans Return, he's also got The Garfield Movie dropping later this year, a film adaptation of a Stephen King novella with The Life of Chuck and more work as Nightwing on Harley Quinn. But what he really wants to do is a romcom.

"I want to do something like a romantic comedy. That'd be kind of fun. You see me as the lead, and it’s a romantic comedy where we see a different love story and what that looks like," said Guillen, who identifies as queer. "I don't think we've seen it yet. I kind of want to steer my focus on that. Something that could be great for everyone to see. Love comes in different shapes, sizes, and colors. It'd be great to give a different take on a love story."

Just don't ask him to pick out his on-screen love interest, as he has a history of manifesting things without knowing it.

"When I did Werewolves Within, they asked me who my costar should be. And I was like, 'Who would be my husband in this movie?' And I said it should be someone who's charismatic ... he could sing and have a good time. Someone like Cheyenne Jackson. And they called Cheyenne Jackson," he explained. "So, I have to be very careful about who I say. Cheyenne was great, but it was so funny because my wish came true. So you have to be careful what you manifest, because it may come true!"