The Third Avengers: Doomsday Trailer Leaked, And Doctor Doom Isn't In It

Marvel's audacious "Avengers: Doomsday" marketing campaign has started roughly a year before the film's premiere, and everything is leaking online before it plays in theaters. Marvel is using "Avatar: Fire and Ash" to promote next year's massive "Avengers" crossover in an unexpected way. Each week, a new teaser is released before "Avatar 3" starts playing, for a total of four short trailers. After the Steve Rogers (Chris Evans) and Thor (Chris Hemsworth) clips, we expected to see Robert Downey Jr.'s Doctor Doom in the third clip, but that's not what's happening. Instead, Marvel is going for a different shock-and-awe effect this week. The third "Doomsday" trailer features Fox's "X-Men," beloved Marvel characters that we've hardly seen in the MCU so far, including James Marsden's Cyclops.

This may sound like we're going into spoiler territory with no warning, but that's not the case. Marvel has already explored various alternate realities since "Avengers: Endgame," giving us a glimpse of at least one world where live-action X-Men exist. In "Doctor Strange in the Multiverse of Madness," we saw one variant of Professor X (Patrick Stewart). Then, "The Marvels" showed us Kelsey Grammer's Beast. Add "Deadpool & Wolverine," and the Marvel Cinematic Universe got Deadpool (Ryan Reynolds), Wolverine (Hugh Jackman), and Gambit (Channing Tatum).

Fast-forward to late March of 2025, and Marvel hosted a surprise "Doomsday" cast reveal. The studio disclosed the names of 27 actors during an event that lasted five hours and 30 minutes and generated 275 million views. Marvel confirmed that Patrick Stewart, Ian McKellen, Alan Cumming, Rebecca Romijn, and James Marsden would appear in "Doomsday." X-Men fans already know these are the actors who played Professor X, Magneto, Mystique, Nightcrawler, and Cyclops in the Fox movies. With that in mind, the third "Avengers: Doomsday" trailer isn't a big spoiler.

Unlike the Steve Rogers and Thor clips that Marvel already played in theaters, the third "Doomsday" trailer features multiple characters. The older variants of Professor X and Magneto are in the teaser, and they appear to be on friendly terms, sharing a game of chess. However, there's a feeling of impending doom. We don't get to see Doctor Doom attacking this reality, but the X-Men are fighting something. "Death comes for us all, that's all I know for sure," Ian McKellen's unmistakable Magneto voice is heard as the camera shows us a world on the brink of destruction. "The question isn't: 'Are you prepared to die?' The question is, 'Who would you be when you close your eyes?'"

"Death comes for us all, that's all i know for sure. The question isn't are you prepared to die, the question is who would you be when you close your eyes?" #AvengersDoomsday pic.twitter.com/8WJ2oP69dL

— Demet (@demetherself) December 27, 2025

The short clip then switches to a battle scene featuring Cyclops wearing an almost accurate costume from the comics. Cyclops has had a long day of fighting. He removes his visor to blast something at full force, and we see his face partially covered in what could be someone's blood. Behind him, the massive legs of a Sentinel appear. That's how the video ends, teasing a battle scene featuring a team of mutants similar to the Fox "X-Men" movies, facing a significant threat. 

Avengers: Doomsday – X-Men teaser description:

Opens with dark scenes inside the X-Mansion. The camera then pans to the metal plate that says Xavier's School for Gifted Youngsters. It moves slowly around the mansion until we see Xavier in the distance, seated in his chair.

His... pic.twitter.com/fdpNeDwHny

— Demet (@demetherself) December 28, 2025

It's unclear what that big threat might be, but MCU fans will undoubtedly suspect it's Robert Downey Jr.'s Doctor Doom. He is the main villain of the upcoming "Avengers: Doomsday" and "Avengers: Secret Wars" movies, and the likeliest threat to the X-Men.

The MCU has delivered the first footage of Doctor Doom via a credit scene at the end of "The Fantastic Four" movie earlier this year. However, we didn't see the villain's face or mask, as Marvel only showed his back. With the third "Avengers: Doomsday" trailer leaked, we know Doctor Doom will not show his face for at least a week. There's a fourth short trailer left for "Doomsday," which will play next week. Early rumors claimed the fourth "Avengers: Doomsday" clip would be longer than the first teasers, each about 80 seconds long. If that's the case, a full "Avengers: Doomsday" trailer should feature RDJ's Doctor Doom in some capacity.

The alternative is for Marvel to give Doctor Doom a brief introduction via a short teaser next week, and release the full-length trailer in the coming months. Super Bowl LX in February is a good place to make a big impression with fans. There's also the possibility of Marvel featuring a different character than Doom next week, to further delay the "Doomsday" reveal MCU fans are dying to see. 

After all, the unconventional "Doomsday" marketing campaign shows Marvel wants to surprise fans at every step, and there's plenty of time for Marvel to show Robert Downey Jr. in full Doctor Doom costume in an official trailer. "Avengers: Doomsday" hits theaters on December 18, 2026, with "Avengers: Secret Wars" to follow on December 17, 2027.