Even after four seasons of NBC's "Grimm," Nick Burkhardt (David Giuntoli) is still not your typical Portland police detective. As a supernatural guardian known as a Grimm, Nick's responsible for maintaining the peace between humans and the creatures classified as Wesen. Eventually, Nick found his groove, but his Grimm duties have become more complicated lately.

This season, Nick's Grimm powers were magically stripped away, but he eventually found a way to regain them. Nick mentored Trubel (Jacqueline Toboni), a fledgling Grimm, who went from loose cannon to valued friend. However, the most devastating blow came when Nick recently discovered his human fiancée, Juliette (Bitsie Tulloch), had been transformed into a Hexenbiest, a witch-like Wesen and mortal enemies of the Grimms.

Ahead of tonight's explosive episode, "Bad Luck," Giuntoli spoke to Spinoff Online about how Nick has dealt with Juliette's shocking revelation about being a Hexenbiest. He also discussed making uneasy allies, game-changing developments and Grimm's renewal for a fifth season.

Spinoff Online: "Grimm" has already been renewed for a fifth season by NBC. How rewarding is it growing with your character and attracting such a loyal fanbase?

David Giuntoli: It's every actor's dream to work on a show for as long as we at "Grimm" have been allowed to do. It's been incredibly rewarding to watch Nick grow from feeble, scared little Grimm to mean, empowered Grimm. We're absolutely humbled at the chance to make a fifth season.

Looking at this year, what did Nick learn from temporarily losing his Grimm mojo?

Nick has always had a complicated relationship with his Grimm powers and destiny. For the first several years, he really wanted nothing to do with them and wished for it to go away. When he lost them, Nick really understood what he had. He came to see the value and the necessity for him to have these powers. And, Nick wanted them back, dearly. The world needed to have him back, too.

At the end of the last episode, "Trial by Fire," Nick finally learned that Juliette is now a Hexenbiest. How does he take that news and what is his first move?

His first move is to quiet the storm and try to convince Juliette it's going to be okay. He has to let her settle down and sort of shake hands with the tornado. Also, Nick is going to try to figure out a way to reverse this horrible side effect. As the season goes on, it all goes very wrong.

It's been suggested Juliette's transformation might be permanent. Being a Grimm, how does this prospect impact Nick?

I think becoming a Hexenbiest, it's almost like the brain completely transforms. Juliette becomes somebody else completely. The prospect of being a happy, day-to-day Joe Schmo is completely disintegrating for Nick.

At this point, Juliette hates me with a vengeance. The Hexenbiest in her is very strong. She probably sees me as her mortal enemy.

The villainous Adalind certainly knows how to push buttons. Will viewers be treated to a confrontation between Nick and her anytime soon?

Things get a little weird with Adalind and Nick. She will enter my world, but it's not really a confrontation. It's nuts.

The Royal Family have been searching for Adalind's baby, Diana, but Nick obviously had bigger problems to contend with. How will those two worlds collide moving forward?

In a huge way. The Royal Family deals me a huge blow at the end of the season that is unforgivable. You'll see.

The producers promised that "Grimm" is going to become even darker. What does that mean for the main characters?

Think "Game of Thrones." Those are the kind of stakes we are working with now. Everyone is in peril. Nobody is safe in the world of Grimm at this point.

Sgt. Wu (Reggie Lee) finally learned Nick's secret. What has that knowledge and Wu's presence added to Team Grimm?

It's just so fun. Wu is a wonderfully colored character. It's fun to hear his snarky, humorous remarks about the world "Grimm" lives in. He's kind of this outside character, who is commenting on this world that is my reality, and how ridiculous it is. It's a nod to the viewers.

One thing about "Grimm" is it doesn't take itself too seriously. It always has the ability to poke fun at itself and wink at the camera a little bit in the writing. A lot of that is written through Wu.

Trubel will reportedly be returning. What brings her back to Portland?

I don't know yet. I know she'll be back, but we haven't gotten there yet.

The Season Two finale saw Nick become a zombie. Last year, he lost his Grimm abilities. What kind of discussions have you had with the producers about where things will end in season four and how it will affect the status quo?

I don't ask, and they don't really tell me. I don't think they want to. Then, actors don't have an opinion and they don't have to deal with us. They are wise. I know that Nick will be in a darker place than he has ever been because I know about a couple of events that take place in his personal life. The only other moment in the series that compares to what's about to happen to Nick is when he found out he was a Grimm. It might even be bigger.

"Grimm" airs Fridays at 8 p.m. ET/PT on NBC.