The Sorcerer Supreme is set to play a major role in Avengers: Infinity War, as evidenced by the trailers and the fact that he is the keeper of the Time Stone. But that hasn't stopped fans from wondering about a sequel to Doctor Strange.

At a recent screening for the 2016 Marvel Studios movie, screenwriter C. Robert Cargill revealed his plans for the antagonist of a potential Doctor Strange 2, saying simply that "Nightmare will be the villain."

Marvel Comics stories depict Nightmare as an entity of the Dream Dimension who feeds off of latent psychic energy. Of course, the end of the first film also teased that Baron Mordo will take on a villainous turn, and Cargill spoke about those two characters getting involved with each other.

"Marvel movies work in threes. They also work outside of their threes. Some of the better Marvel films have more than one villain in them," Cargill said to Movie Web. "Me and Scott have not laid the groundwork for it but what I can say is that I have a feeling that whatever Nightmare is involved with, Baron Mordo, being somebody who considers himself the defender of natural law will have something to do with it."

Cargill spoke about Mordo's arc throughout his plans for a series of movies, revealing it's one of the reasons why Chiwetel Ejiofor signed on to play the role, while stressing nothing is guaranteed for the future.

"For those of you who have ever read the comics, you know that Baron Mordo has a very particular arc, and that's something we discussed with Chiwetel while working on the first movie," he said. "And part of the reason Chiwetel wanted to play Mordo was because he has a definitive ending as a character and it's such a fascinating ending. And I do know that whether we're attached or not, that Marvel plans on working towards that ending and fully realizing Mordo as more than just a cardboard cutout villain, but actually taking him to kind of Loki levels of awesomeness. That's the goal with him."

Cargill, who has frequently collaborated with Doctor Strange director Scott Derrickson, makes it clear that there currently aren't any plans in place for a sequel movie. The character will next appear in Avengers: Infinity War, with Benedict Cumberbatch reprising the role as the Sorcerer Supreme teams up with Earth's Mightiest Heroes to take on Thanos and his Black Order.

Avengers: Infinity War premieres in theaters on April 27th.