Dormammu could prove to be a bigger threat than Thanos in Doctor Strange in the Multiverse of Madness. Thus far, the Mad Titan has been the most powerful force Earth’s Mightiest Heroes have had to contend with in the Marvel Cinematic Universe, but an existing MCU villain has the potential eventual to eventually overshadow him in terms of power.

Prior to Thanos’ attack on Earth in Avengers: Infinity War, the planet was threatened by Dormammu, Doctor Strange’s biggest enemy in Marvel Comics and the evil ruler of a mysterious realm called the Dark Dimension. Because Kaecilius (Mad Mikkelsen) was using his minions and his command over the magical acts to destroy the Sanctums on Earth, it became possible for Dormammu to invade the planet, as it was these magical sanctuaries that kept him at bay. However, Doctor Strange (Benedict Cumberbatch) concocted a plan to stop him. After trapping Dormammu in a time loop spell, Strange made him promise to leave Earth alone.

Related: Every Future Marvel Movie Doctor Strange 2 Could Set Up

It appears that Strange has stopped Dormammu from being a problem in the future, but he shouldn’t be counted out so soon. After all, their comic book counterparts have made similar arrangements in the past, with Dormammu finding loopholes that let him proceed with his plans anyway. If and when Dormammu gets out of his deal with Strange, he could emerge as the most dangerous villain ever encountered in the MCU. That will be especially true if for some reason Doctor Strange and Scarlet Witch (Elizabeth Olsen) are forced to fight him in the Dark Dimension.

Doctor Strange talking to Dormammu

In Marvel Comics, Dormammu’s power is unrivaled when he’s at home in the Dark Dimension. He’s weaker when in other places, but nearly unbeatable when in his own realm where he can draw from its power. Strange was able to resolve his conflict with the Lord of Chaos without violence in the first movie, but depending on the direction of Doctor Strange 2, a real battle between them may be on the horizon. Doctor Strange used originally beat him by creating a time loop with the Time Stone, but now that the Infinity Stones are gone, that won’t work in the sequel, meaning Dormammu can serve as the MCU’s strongest villain yet.

There’s evidence indicating Dormammu has the capabilities to outdo Thanos. In Avengers: Infinity War, Doctor Strange held his own against Thanos for a while and was capable of fighting with the Mad Titan. But in Doctor Strange, he didn’t even attempt to beat Dormammu. That’s because he had the intelligence to know that he didn’t possess the means or the power to defeat him. He understood that a victory in combat was impossible against the villain, but apparently didn’t feel the same way about Thanos. In the comic books, Dormammu is without a doubt one of the most powerful entities in existence, and it stands to reason that the same is true for the MCU version of the character. If Doctor Strange 2 lets Dormammu unleash his full potential, he could become the MCU’s overarching big bad for Phase 4 and Phase 5.

More: Doctor Strange 2: Every Theory About What Starts The Multiverse of Madness

Key Release Dates