Michael Johnston and Hannah Marks in "Slash"

Hannah Marks’ first brush with fan fiction arrived when she played Missy Kallenback in “The Amazing Spider-Man.” A small role in which she harbored a crush for Peter Parker, Marks found it significantly expanded upon online in all kinds of interesting ways.

“Because the character didn’t exist before the movie, it was cool to see people create their own stories just from the scenes from the film,” said Marks.

Just as the fans had added new dimension to the character she had played, Marks returns the favor in “Slash,” Clay Liford’s often side-splitting yet sensitive comedy where she plays Julia, a brash teenager whose sexually-charged prose may be inappropriate for school but has found a home on an online forum called Rabbit’s Hole. To her surprise, the site is frequented by a classmate named Neil (Michael Johnston) who finds refuge in writing sexually-charged fantasies set in the world of his favorite sci-fi series “Vanguard,” and the two’s already complicated emotions as young adults get even more so as they grow closer to one another, not entirely sure of their sexual identity.

As Julia, Marks is particularly affecting, exuding a deep confidence in her writing ability and who she wants to be without knowing who she is in the current moment as a troubled homelife she’s eager to put behind her and the unexpected affections of Neil throw her off her game. The performance is consistently surprising, but not unexpected from Marks, who could kill with an eye-roll in her turn as part of a band of riot grrrls in Roxanne Benjamin’s segment of the anthology horror film “Southbound” and has parlayed the punk into her recent work on the BBC America series “Dirk Gently’s Holistic Detective Agency” where she may suffer from debilitating psychological fear but nonetheless rebels through her drum kit.

With “Slash” now in theaters and on VOD, following a premiere earlier this year at the SXSW Film Festival, Marks spoke about her foray into fan fiction, finding the chemistry with her co-star Johnston and shooting at a live Comic-Con.

Michael Johnston and Hannah Marks in "Slash"How did you get interested in this?

I had auditioned a really long time ago, with the scene where I’m reading the erotic fable that [my character] wrote and reads in front of the classroom. I put that on tape and then I didn’t hear about it until I think a year later, but I really loved the character. She is super in love with writing and I [really appreciated] that because I love writing myself and she’s so passionate. That’s one of my favorite qualities in people, so it was so exciting to play her because you don’t often see that with 16-year-old girls onscreen. Usually, they feel lost and Julia knew exactly what she wanted.

When it’s a character that’s a writer, did you actually have a feel for what your character would write — perhaps with more background to draw on that may not have been in the film?

We talked a lot about the characters’ feelings and how they interact with each other. There wasn’t lots of erotic fan fiction reading on set. [laughs] Although that probably would’ve been a lot of fun. But we all got together and watched “Welcome to the Dollhouse” for the movie and we also had about a week of rehearsals before we started, so a lot of our work was actually just scene work and going through the script together.

Michael has said you wanted to bond immediately with him once you were cast – what was important about forging that relationship with him?

We wanted the relationship to feel real and it was important for us to have a connection because we’re in almost every scene together. If you don’t buy that relationship, you won’t buy the movie, so we just tried to spend as much time together as possible to really get to know each other and get used to being around each other because so much of that is just being used to each other’s company and each other’s energy. It isn’t even how much do I need to know about this person. It’s just being physically around each other where you get that chemistry. Doing a lot of the scenes at Neil’s house were important because that’s when we first start flirting with each other and that was important for us to get right and to have that chemistry feel real.

What was it like working with Clay Liford as a director and having him as a resource? He really seems to know this world.

Clay was incredibly open and collaborative. It was incredibly nice working with him. He’s one of the sweetest guys on the planet and really an amazing writer. I have no idea how he was able to get so specific and detailed with these characters. I don’t even think he was aware of this world before he started writing [the script], so I think it’s really cool that he took a risk and dove right in because I think it is a risky subject and it’s very niche, but a lot of my favorite movies are movies that take a small, unknown subject and they get really, really detailed and I think he completely accomplishes that with this movie.

Michael Johnston and Hannah Marks in "Slash"He told me some of the convention stuff was shot on the live floor — what was that like?

That was actually the first thing we did, so that was part of our bonding experience because we went to Houston Comic-Con and we dressed up and pretended to be these totally fictional characters that we love in the movie. Because Michael and I hadn’t been to Comic-Con before [in real life], we got to experience our first-ever Comic Con and it was a perfect way to start shooting. Nobody really knew that we were filming because we stripped down the camera pretty small and were incognito.

Is it true that the costume had some issues due to a latex allergy?

Yeah, I’m allergic to latex, so those elf ears were driving me crazy! They’re often a little droopy throughout the course of the film because [of how we applied the] stick tape. [laughs]

Was filming in Austin fun?

It was really nice because it’s such a cool city. I had never spent any time there and we got to go back for SXSW, which is a perfect place to premiere it.  Lots of good music and food – it was exciting. It’s cool to go to a new city when you’re working there because you get to experience it in a different way.

In general, has this been an exciting year? With this and “Dirk Gently,” it seems like you’ve got a lot going on.

Yeah, it’s been a really great year. I feel so lucky to be on “Dirk Gently” – I love the show and I love the people that I work with and Max Landis is an incredible writer. We just got a second season and we’re all beyond thrilled. I also just finished a great movie that I produced based on a novel that I loved called “Almost Home.” It’s about homeless youth in L.A., so the experience was not necessarily fun because it’s very heavy subject matter, but it was very emotional for all of us and it was my first time producing a feature, so that was a big step forward for me, and now we’re promoting “Slash,” so it’s beyond anything that I hoped for.

“Slash” is currently playing in Los Angeles at the Laemmle NoHo 7. It is also now available on iTunes. A full list of ways to watch are here.