While plenty of Marvel Universe heroes possess awe-inspiring powers that make them dangerous opponents, there are some that don't rely on super powers to be effective or frightening. Two of the most fearsome from the latter group are the Black Widow (AKA Natasha Romanoff), a former KGB assassin turned S.H.I.E.L.D. agent and Avenger, and the Punisher (AKA Frank Castle), a highly trained Marine who launched a one-man war on crime when his family was killed by the mob.

On March 25, these two experts in the arts of war and espionage will collide and then team up for a mission that pits them against Leviathan, a high-tech global terrorist network. The story of the mission and the events leading up to it will be told in the Madhouse-produced direct to DVD/Blu-ray animated film "Avengers: Confidential: Black Widow & Punisher" from Marvel Animation. Writer Marjorie Liu wrote the film's story and spoke with CBR News about the project and her affection for the film's heroes.

CBR News: Marjorie, looking at your website it appears you've done some writing in video games based on your "Dirk & Steele" novels, but it doesn't look like you've done any writing for film. Is that true? How was your experience writing the story for "Avengers Confidential: Black Widow & Punisher?" Was it more similar to penning a comic script or a novel? Or was it drastically different from both?

Marjorie Liu: I had no experience writing for film, but the producers were incredibly patient and led me through the process -- which, as it turned out, was a lot of fun. I think most people rightly assume that Black Widow is one of my favorite characters, but what might not be obvious is that I've been a Punisher fan since I first started reading comics. In fact, I think Punisher was one of the first comics I ever bought-- right alongside the X-Men and Batman. The idea of Frank Castle and Black Widow, together? As adversaries -- and as a team? In my mind, it made total sense. In fact, it seemed perfect. As for the experience of writing the story -- in some ways, it was like creating a very detailed outline for a comic script. A lot of direction, with some dialogue to ground the scene.

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Let's talk a little bit about the world you're playing with in the film. Is this essentially a story that takes place in the world of the Marvel Cinematic Universe? The Marvel Comics Universe? Or is it its own thing that sort of borrows elements from both?

It's pretty much its own thing, but it tracks within the same universe as previous animated Marvel Anime films -- such as "Iron Man: Rise of Technovore."

You wrote several issues of the Black Widow's previous comic series. What is it like returning to the character for an animated feature film project? What's your sense of the Widow in "Avengers Confidential?" How does she compare to the Natasha of the Marvel Universe?

I always jump at the chance to write Black Widow -- whether in her own series, her limited appearance in "X-23" -- or here, in the film. She's an amazing character: brilliant, fearless, dangerous, all mixed up with this devastating condition I like to call "having a heart." I wrote those same qualities into the "Avengers Confidential" character, and though I haven't seen the final results, from my few extended glimpses I think it's safe to say that viewers will see those qualities and another side to Natasha, as well: her vulnerability. An old flame appears in the movie, and it makes her mission a personal one.

As you mentioned earlier, you're a huge Punisher fan and you've written him one other time, albeit briefly, and that was when he was in his FrankenCastle form. What's it like writing the Punisher for this project? What do you find most interesting about this incarnation?

FrankenCastle was a very different project, because it didn't really feel like "Frank" to me. I think of him as quiet, reclusive, an "every man" who just happens to be a cunning, implacable vigilante who can ruin your life in such horrifying ways that simply hearing what he's planning to do will put you in therapy for life. I love it. I tried to give "film Frank" those same qualities, and something more: we get to see what he's like when working as a member of a team. It doesn't soften him, but it does make him slightly more expressive.

How would you describe the initial dynamic between Frank and Natasha when "Avengers Confidential" begins? How do these characters initially view each other?

They're certainly not friends. Natasha has been sent to bring Frank in, and it's not as if he's going to cooperate. But as the movie progresses, they begin to see each other in a new light -- not quite as friends, not as enemies, but something between. A team. And what makes these two such a natural fit is their relentless determination. Frank doesn't give up, ever -- and neither does Natasha. And both of them are amazingly canny, as well. Natasha is the perfect spy, an amazing fighter-- and while Frank isn't nearly as subtle as she is, his instincts and ability to infiltrate (and destroy) are her equal. They are amazing killers.

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The official title of this project is "Avengers Confidential: Black Widow & Punisher." I imagine the focus will primarily be on those two characters, but I understand Nick Fury and some other Avengers will appear as well. Which Avengers will viewers see in the film and what kind of roles will they play?

What's interesting is that the original title was "Black Widow Versus Punisher," which gives a much different tone to the film. That said, the focus is mainly on Natasha and Frank, though Nick Fury plays a substantial role. He's a man who is trying to clean up a mess he feels indirectly responsible for, but he can't officially involve S.H.I.E.L.D. in the investigation. Hence, the need for Frank Castle. The rest of the Avengers -- Hulk, Captain Marvel, Iron Man -- make an appearance in the latter half of the film.

What can you tell us about the plot, themes, and tone of "Avengers Confidential: Black Widow & Punisher?" The trailer suggests that the film

will be sort of a super spy action film. Is that correct?

It's definitely a super spy action film. Redemption is a huge theme of this movie -- that and trust, forgiveness, learning to see beyond the lies that people tell us.

What can you tell us about the obstacles and adversaries the Black Widow and the Punisher are up against in the film? I read a description that mentioned Leviathan. Is this a version of the same terrorist group that appeared in writer Jonathan Hickman's "Secret Warriors" series?

The short answer: Leviathan -- which is definitely related to the terrorist group in "Secret Warriors" -- creates a weapon that endangers the world, as all these weapons tend to do. The more interesting story rests with Punisher and Black Widow, who are both dealing with their own individual demons. The Punisher, who is never conflicted, is put in a position where his brutality is unleashed outside his control, with devastating results. For Natasha, someone from her past returns -- an old flame. And while she never questions the mission at hand, it's not easy fighting someone you used to love.

Finally. I understand your story was turned into a screenplay by Mitsutaka Hirota, a writer who's worked on several anime series including the 2011 "X-Men" series. How does it feel to be involved in this type of collaborative experience where your story is turned into an animated feature? And have you seen any footage from the film yet? If so how does it look?

I was very happy that Mitsutaka Hirota was the screenwriter, as I loved the 2011 "X-Men series." I've seen some footage, and the movie looks great. It'll be somewhat different from the story I turned in -- a necessity of the process, Mitsutaka's own taste, and the constraints of the running time -- but the bones are the same.

I hope you enjoy the film! I'll be blogging about the process and revealing exclusive art leading up to the release -- just check out my blog and twitter feed for updates.

"Avengers: Confidential: Black Widow & Punisher" will be released on Blu-ray & DVD March 25.