Avengers: Doomsday's Mystery Villain Is The Man Who Really Beat Thanos (MCU Theory Explained)

Published Sep 27, 2026, 12:55 PM EDT

Since 2019, Kevin Erdmann has been one of Screen Rant's Senior Staff Writers, covering all kinds of Superhero and Star Wars media with Easter egg breakdowns, theory pieces, breaking news, and more. A huge Star Wars & MCU fan, Kevin also loves Batman (because he's Batman), but could talk for hours about why Nightwing is DC's greatest hero. 

With 8 years of total experience covering entertainment and pop culture, Kevin has gotten the chance to interview top creatives and talent, and has also attended major media events like Disney's D23 convention.

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Although Avengers: Doomsday is just a few months away, there's still so much we don't know about Doctor Doom's mysterious allies. Not only has a group of masked Latverian witches been teased, but Robert Downey Jr.'s Victor von Doom will likely be backed by another masked enforcer as well (who could very well be the one truly responsible for Thanos' defeat).

Question 1 of 3

In 2019's Avengers: Endgame, the surviving heroes work together to retrieve the Infinity Stones from the past to bring everyone back in the present before Iron Man uses the Stones to defeat Thanos and his forces, sacrificing himself in the process. However, the entire "endgame" in question was put into motion by one key hero: Doctor Strange.

Looking at the Master of the Mystic Arts and his role in both the Infinity and Multiverse Sagas, it feels possible that Benedict Cumberbatch's Doctor Strange may end up working alongside Doctor Doom himself, rather than allying with the rest of the Avengers in Doomsday (and Secret Wars).

Avengers Endgame's Victory Was Thanks To Doctor Strange (Only One Way)

In 2019's Avengers: Endgame, Doctor Strange returned alongside the other heroes dusted at the end of Avengers: Infinity War, having been erased from existence for five years before the surviving Avengers brought them back. Despite joining the fray and keeping the battlefield from being flooded, it's easy to overlook how crucial Doctor Strange's role was in taking down Thanos, even if he wasn't the one who actually did it.

In truth, everything that led up to Thanos' defeat was actually by Strange's design, dating back to the ending of Infinity War. Before the battle with the Mad Titan, Strange used the Time Stone to examine all the possible futures and outcomes, determining that there was only one course of action if the Avengers were to win, including giving up the Time Stone to Thanos and allowing him to Snap half of all life out of existence in the first place.

Taking everything that happens after that moment into account, it's pretty staggering to realize just how much pain and suffering Strange effectively allowed in the service of the greater goal and the singular path ahead. When it comes to the long term and ultimate greater good, Infinity War and Endgame proved that Doctor Strange is indeed willing to pay the cost.

"The Grand Calculus" - The Multiverse Saga Has Proven Doctor Strange's Darkness

Things then become even more interesting when you think about Doctor Strange's role in the Multiverse Saga. During the events of 2021's Spider-Man: No Way Home, several villains from other realities are brought to Earth-616 after Peter Parker inadvertently messed up Doctor Strange's spell. As such, the Master of the Mystic Arts demanded the villains all be captured and sent home immediately to prevent multiversal catastrophe, even after learning that some of these villains would be sent back to their deaths.

This results in one of Strange's most telling lines in the MCU's current saga: "In the grand calculus of the multiverse, their sacrifice means infinitely more than their lives."

This line is later repeated in 2022's Doctor Strange in the Multiverse of Madness, underlining the statement as a predominant perspective and outlook from Strange when it comes to multiversal crises like incursions. Likewise, it's well worth remembering in light of Doctor Doom's sentiments in the trailers for Avengers: Doomsday, telling Earth's Mightiest Heroes about consequences and how they're all living "stolen lives." It suggests that Victor sees himself as a corrective force seeking to restore multiversal imbalance. Keeping that in mind, it's not hard to imagine some version of Doctor Strange siding with Doom even in the face of what will likely be some pretty dark methodology, so long as he believes it will ultimately serve the greater good of the multiverse. If he sees Doom's actions as necessary, Strange could likely come to view Victor's path as the only way forward at the end of the Multiverse Saga. Furthermore, an uneasy alliance between the two doctors would have some solid comic book precedence when it comes to Secret Wars.

Doomsday Theory: Doctor Strange Will Be Allied With RDJ's Doctor Doom

One of the biggest clues comes from the specific design of the aforementioned masked enforcer who was reportedly codenamed "Boris" during Doomsday's production. After all, released images of the character feature what looks to be a third eye printed onto the character's mask, which naturally draws comparisons to Doctor Strange and the third eye he recently acquired in the MCU after using the Darkhold in 2022's Multiverse of Madness.

Taking all of the above into consideration, Doctor Strange being this masked enforcer absolutely lines up with Strange's comic book history as well with 2015's Secret Wars event from Jonathan Hickman and Esad Ribic.

As incursions are gradually wiping out the multiverse until there is nothing left in 2015's Secret Wars, Doctor Doom takes it upon himself to claim the power needed to save all existence by creating Battleworld, a new realm forged out of the remnants of various realities, and placing himself as its ruler known as God Emperor Doom. On the page, Strange was at Doom's side the entire time, having acknowledged the dark necessity of Doom's designs and even serving as "Sheriff Strange" and Victor's key advisor in the new world created in Doom's image, one of the few who remembered existence as it had been.

While we don't yet know the exact pieces, it has been confirmed that the MCU is taking inspiration from 2015's Secret Wars just as much as 1984's original event. Based on everything we know to be true thus far, Doctor Strange secretly being this masked Latverian enforcer makes a lot of sense, especially seeing how there's been very little in the way of official confirmation regarding Strange's involvement in either Doomsday or Secret Wars, despite being one of the MCU's most multiversally-focused heroes in recent years.

All that being said, it'd also be very cool if Strange eventually turns on Doctor Doom in the upcoming MCU movies, just like he does in 2015's Secret Wars. After all, it's not as if he still has the Time Stone and would have the same level of absolute certainty he had in the last two Avengers movies. A time could come when Strange could see the possible flaws in Doom's design. At any rate, it's going to be very exciting to learn what's in store for Doctor Strange as we get closer to the end of the year with Avengers: Doomsday's release.

Avengers: Doomsday releases in theaters on December 18th from Marvel Studios.

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  Victor von Doom

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  Reed Richards / Mr. Fantastic

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  Thor

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  Vanessa Kirby

  Sue Storm / Invisible Woman