When Doctor Strange hits theaters next month, it will be with a fair bit of reinvention from the comic book source material. While director Scott Derrickson and the folks at Marvel Studios have made it clear that they’re staying true to Stephen Strange’s basic arc and the far-out interdimensional magic envisioned by Steve Ditko, they’ve also famously gender and race swapped The Ancient One, given Wong a lot more power, and for now, they’re establishing Chiwetel Ejiofor’s Baron Mordo, not as a mortal enemy to Doctor Strange, but as an ally and a comrade under The Ancient One’s tutelage.

Earlier this year, I visited the set of Doctor Strange just outside of London where I had the chance to join a few journalists for a chat with Ejiofor. He talked about ditching the two-dimensional arch villainy of his comic book counterpart, where we meet Mordo in Doctor Strange, the purity of his dedication to The Ancient One and her teachings, and his complicated relationship with Doctor Strange. Check out what he had to say in the interview below.

We’ve gotten to hear a little bit about Mordo and how he’s going to be more of an ally than he is in the comic books. Did that change the way you approached the character?

CHIWETEL EJIOFOR: The source material was very helpful in terms of trying to construct an overall understanding of him and his relationship to the place, Kamar-Taj, and his relationship to the Ancient One. Of course in the source material, it’s a much more two-dimensional story in some ways. But one of the richest things of this is finding the other space and really trying to create something that’s very three-dimensional and a person who has a real history and a real background and, as in the comics, has a very good relationship with Kamar-Taj and the Ancient One and by extension Strange himself. So I definitely thought about the character in terms of comics and really understanding the ways in which the character changed and still keep the essence of who he is and add this more three-dimensional aspect to him.

Where we meet him?

EJIOFOR: We meet him in Nepal. We meet him in Kamar-Taj. And he is one of the first allies to Strange and he wants to bring him into this community, this very special, knit community, and see if Strange can fit in and create a home for him there–a place where he can learn the skills of Kamar-Taj and get in contact with these forms. I think that Mordo is the first to recognize the potential in strange and becomes his primary advocate, initially. Their relationship is complicated. In some ways they’re quite similar but that lends itself to tensions between them. But overall he is the tutor that really brings him in.

Is there a camaraderie between them?

EJIOFOR: I think it starts with Strange as the pupil. Strange is somebody who is trying to find out what all of these things are and find the secrets of these place. And I think it develops into something deeper and richer. Yes there is a camaraderie but it’s also a kind of mutual respect as they gain an understanding of each other. And also with the problems that they face and the enemies that they face and their ability to work together to triumph or try to win means that they have a bond. I think the three of them develop this bond with the Ancient One, this mutual respect.

Has he known the Ancient One for a long time?

EJIOFOR: Yes, as long as Mordo has been here, the Ancient One has also – and well before. There’s an enormous amount of respect and dedication to the cause and to the Ancient One specifically, who is, for whatever version of hell Mordo was blown in from, which probably isn’t a million miles away, psychologically, from Strange’s journey, in terms of finding it impossible to continue. He had to find something else, something new, something radical to restructure oneself.

In the comics, it’s jealousy that turns Mordo. Is that something you’re playing with?

EJIOFOR: I don’t think of him as a kind of envious or jealous entity. I think he’s much purer than that. That’s what I mean by the comics create a slightly more two-dimensional aspect. But the place, Kamar-Taj, what it means and what it means to Mordo, is so strong and his defense of it is so deep and his loyalty is so committed–to the ideas of Kamar-Taj, to the reality of Kamar-Taj, and to the Ancient One that he would react to any perceived threat but it wouldn’t come from a place of envy but from a place of protection and loyalty.

Physicality of magic, motions of magic. How does that affect the way you play the character?

EJIOFOR: There’s a lot of physicality in the film. It’s a really important part of the story. When we bring in Strange to this world, the first thing we introduce him to is the physicality of the world, how we create these other dimensions and the magic that we do. And also the physicality of how we fight and what our combat stances are. So very immediately he’s introduced into a physical world and that affects all of the characters in the space, regardless of what we’re doing. All of that is fundamental. The physicality is fundamental to these characters and what Strange has to learn in.