For actress Claire Coffee of NBC's upcoming supernatural series "Grimm," stepping into the role of an esteemed assassin is a refreshing contrast to her good-girl characters of the past.

Based on the classic Grimm’s Fairy Tales first published in 1812, "Grimm" will air Fridays this fall with “Buffy the Vampire Slayer” and “Angel" writer-producers David Greenwalt and Jim Kouf at the helm.

The series brings fairy tales to life as homicide detective Nick Burkhardt (David Guintoli of “Turn The Beat Around”) discovers he is a descendant from an elite group of hunters known as Grimms, who seek to keep humanity safe from supernatural threats. As a result, he is forced to shoulder the responsibilities of the Grimms' legacy and face down the boundless mythology first documented by Wilhelm and Jacob Grimm.

Coffee will play Schlauraffen, a top assassin who works for the creatures that embrace the darker side of the Brothers Grimm world.

"I am excited to be a part of the underworld instead of a nice girl like usual," Coffee said in a recent interview with our sister site Airlock Alpha. "I don't get to play these kind of ruthless, evil characters … often. As an actor you want to play a character as different to yourself as possible. And I like to think of myself as a nice person. So it's fun in that way.

"And also, I love the fantasy and sci-fi genres; so to get to be a part of that instead of just watching it is really exciting for me."

A production of Universal Media Studios and Hazy Mills Productions, the series is executive produced by Sean Hayes ("Will & Grace") and Todd Milliner (“Hot in Cleveland”).

Marc Buckland ("My Name Is Earl ") directed the pilot, which was penned by Greenwalt and Kouf.

The remaining 12 episodes of Season 1 will lens next month. Should ratings prove strong, nine more episodes may be added to the season.

Coffee feels the series has a good chance to excel with fans of the genre.

"I think it's kind of a brand new take on the fantasy genre," she explained. "It's not dystopia, but it's that idea. And I think it's like watching sci-fi movies where it's the world, but with a little shift. And so it really gets your imagination going.

"And it's very scary. And I think, watching the pilot, there are a lot of great, old-fashioned scares in it. … The reality is so dark that it evokes quite a bit of an emotional response."

Another selling point for Coffee was the involvement of Greenwalt and Kouf, who hold considerable experience crafting supernatural tales.

"They are really great guys to work for," she said. "They are kind and supportive and they are keeping you in on their process the whole way. And I think they come from a background where they have an understanding of this audience and what the audience wants to see."

Moreover, the cast will be a strong draw for the audience, according to Coffee.

"It has a bunch of characters that are individually interesting adding to the landscape," she said. "And I also think there is that element of humor with Silas [Weir Mitchell], who plays the big bad wolf. He is great. And I think Silas will be a breakout right away. He grounds it, for sure, at least in the pilot. And then you realize that the guy I'm connecting to as an audience member is one of these fairy tale creatures. So it's a fun way to travel through the world.

"The two of them [Mitchell and Guintoli] are really good actors. And I think David brings this kind of intense innocence ... Because he is a cop and he is very strong, but he is just so wide-eyed that you really buy that he is going through this, and you really buy that he is freaked out but keeping it together seeing all these crazy creatures for the first time."

Coffee, who was 5 years old when she started her acting career in theater, played Nadine Crowell on the soap opera "General Hospital" for two seasons and has guest starred on a number of prime-time shows, including "CSI: Miami," "NCIS," "Bones," "The West Wing."

She is currently starring in the TNT series "Franklin & Bash," which airs Wednesdays at 9 p.m. ET. In addition, Coffee is in the initial stages of developing a sci-fi feature.

View a preview of "Grimm" here.

"Grimm" also stars Bitsie Tulloch (“Quarterlife”), Russell Hornsby (“Lincoln Heights”), Sasha Roiz (“Caprica”) and Reggie Lee (“Persons Unknown”).