Marvel’s latest superhero movie, “Doctor Strange,” debuts on Friday. And while there’s plenty of anticipation to see Benedict Cumberbatch don the Doctor’s cape, it’s a man behind the scenes, writer Jon Spaihts, who has a truly busy year ahead.

Spaihts was not only tasked with helping to create the world of “Doctor Strange,” but also with helping to jump-start Universal’s classic monster universe, beginning with “The Mummy” reboot, which stars Tom Cruise and bows next summer. The scribe’s long-awaited space adventure “Passengers,” directed by Morten Tyldum, is making its way to theaters in December, and toplines Jennifer Lawrence and Chris Pratt.

In an interview with Variety, Spaihts talks about the excitement of building the “Doctor Strange” world, working with not one, but two Marvel superheroes, and his plans for a recently announced Van Helsing movie.

Many who aren’t big Marvel fans don’t know about “Doctor Strange.” How excited or nervous were you to introduce him to them?

It felt like a lifelong dream come true. He really has been my talismanic character since I was in 4th grade or something like that. He’s been my favorite forever.

What’s the Marvel experience been like? What was different from your previous experiences?

It was a very open and collaborative process, which I loved. They came to the table without preconceptions — and this was the director Scott Derrickson, who was on board just before I was, and Kevin Feige, the grandmaster of the Marvel cinematic universe, and Steve Broussard, the EP. Four of us sat down and talked for hours about what a “Doctor Strange” story could be, and we were not married from the beginning to telling an origin story or to a particular arch villain, or story arc.

We really threw the doors open to all the possibilities. In the end, we were brought home to the origin story because it’s simply so good, and I do believe it’s the best comic-book origin story there is.

How helpful was it to have Derrickson along from the start?

It was a privilege to work with the guy. He’s a formidable filmmaker and a lovely person. To be able to sit together in a room over so many hours talking stories meant that we were able not just to talk in story points, but to talk in images, and so we were constantly sending photographs to each other and showing each other videos and talking about visual representations of things, as well as the hardcore story and the dynamics of the plot.

We rolled up our sleeves and of course had the amazing creative machine of Marvel behind us, so there were concept artists working even while we were breaking down the story, and turning out images and possible representations of the things we were inventing, while we invented them.

The film is filled with Eastern mysticism, faith, and religion. How much of that was from the comic book and how much from your own research?

It definitely has roots in the comic. The comic, consisting of more than 50 years of material, is all over the map about Eastern mysticism, and sometimes is parodying very dated tropes, and sometimes it’s reaching profundity. We aimed in this film to actually say something meaningful about enlightenment, about transcending the ego, about what it means to break through to a wider understanding.

So I think some of it flowed from Derrickson’s personal beliefs and mine and the philosophical discussions we had in the room as well as notions in the comics or other fiction.

Strange is a unique character. Did it help to know you had an actor like Benedict Cumberbatch to carry the role? Did you feel like you needed to up your game given who was playing the part?

It certainly was incredibly reassuring to know there was an actor of Benedict’s intelligence and humanity. There’s nothing that we could write that could be beyond him. The entire cast is gold standard, so it required us to raise our games as high as we could, but the nature of the character is so rich that all we really had to do was render that and respect it.

This is a man with cosmic power in his hands, but his hands are crippled. This is a person who loves knowledge, but who has to come to grips with the fact that knowledge is imperfect and incomplete, and with the fact that there is a wider knowledge of the universe to be gained. This a person who is totally full of himself, who has built his world around himself and who has to get over himself to get on, and that’s great material. It’s a fundamentally sound story.

Did you think about limiting scenes of the Doctor’s arrogance and selfishness?

I think the overarching arc always made sense. What was tricky was the fine tuning. A film is pretty small — ultimately, it’s just a couple of hours of storytelling — and little things cast long shadows. If he’s a little too angry in this scene or that scene, it may loosen our affection for the character. If things come a little too easily for him, it may reduce the stakes of the story. All of those tiny changes have profound effects. And so the real trick, because he is a man of such contradictions, was the balancing act.

You have a busy year with “Passengers,” too. Were you working on both films at the same time?

The “Passengers” script was much older than [“Doctor Strange”] — the bones of it went much farther back — but the production for the two films did overlap, so I did the outlining of the first draft for [“Doctor Strange”] and then Scott Derrickson, himself a very fine writer, and his writing partner Robert Cargill took over. I went off and made “Passengers,” and then I was able to come back and do some finishing work on “Doctor Strange” at the end of the process.

When you were polishing, was there any overlap or were they two unique trips in their own right?

There were moments of harmony between the two projects, and I felt similar ideas and themes moving through them. But they’re set in such different worlds that I never felt like they were too similar.

You were working with two Marvel heroes in Doctor Strange (Cumberbatch) and “Guardians of the Galaxy’s” Star-Lord (Chris Pratt), even though “Passengers” didn’t feature him in that role.

I was on set for four months with Pratt and we laughed about that. In fact, the production of “Guardians 2” was in prep on the same studio lot we were on in Atlanta, so James Gunn came by the set occasionally, and you could look through some of the other studio’s doors and see parts of their sets going up.

At the end of the project, Chris didn’t take a break. Mr. Pratt walked off our sound stage, across the lot, straight from our starship to that starship, and he went straight into the production of “Guardians 2.”

Did you bump into Kevin Feige on set at all?

I didn’t see Feige, although there were Marvel people going in and out. I was so deeply embedded in the “Passengers” production that I barely saw the light of day. We were doing 15-hour days sometimes and I was on a soundstage if I wasn’t sleeping.

How’s the Van Helsing project coming along?

I’m really excited about Van Helsing. I think we’ve created a modern version of the monster-hunter that will really stand the test of time. I’m incredibly excited to see him released into the larger Universal monsters cinematic universe. We’re waiting to see how the film will move forward, but I have high hopes. I think there’s a very good chance that it may be the next thing down the line.

Anything you’re looking forward to next that’s different, or are you sticking with big-budget tentpoles?

I am leaning increasingly toward directing a film, so I have a shortlist of stories that I’m refining, trying to winnow, trying to choose the one. “Passengers” was a wonderful film school. I wasn’t just on set every day, I wrote and shot some viral ads for the movie that will be out later as well as a VR project I helped to create. It was a great primer in filmmaking and it only intensified the bug I already had to skipper a film. So I think the next thing on the drawing board, in the biggest way, will be figuring out which movie will be mine to shoot.