Doctor Strange in the Multiverse of Madness introduced Earth-838 to the MCU, a place where the Avengers weren't the pinnacle of heroism they were on Earth-616. That spot was filled by the Illuminati, a group of superheroes from various teams (the Inhumans, Fantastic Four and X-Men) keeping their reality in order.
The team consisted of Captain Carter, Mister Fantastic, Black Bolt, Captain Marvel (Maria Rambeau), Professor Charles Xavier and Baron/Master Mordo. As hinted at above, one of the most intriguing aspects about this new Earth was that it seemed like the Avengers were never a thing there.
For starters, Multiverse of Madness established that in this reality, the Illuminati defeated Thanos. Further putting into question the existence of Earth's Mightiest Heroes was the fact that Ultron bots were no longer the murderous villains shown in Age of Ultron. Instead, they were loyal servants to the Illuminati.
Now, though, we have an answer regarding the Avengers' status on that Earth, and it sets up a fascinating mythology for the alternate universe.
How Age of Ultron Went in Earth-838
Speaking with Empire, (via The Direct), Marvel Studios Producer Richie Palmer revealed that on Earth-838, Wanda stepped away from her superhero duties because Tony Stark's plan in Age of Ultron to have Ultron protecting the world actually worked.
That, in turn, gave each member of the Avengers the opportunity to retire if they so wished:
"Yeah, we believe that the "838" Wanda had some children and kinda retired. She was happy living a life with her family and didn't need to prioritize being a superhero. Maybe because of the Illuminati, maybe because of some other stuff. [...] But this is a world where Ultron seemed to work the way Tony Stark intended him to work in Age of Ultron. 'A suit of armor around the world,' Tony was trying to get the Avengers to retire [in that movie]. So, imagine [this is a world] where Tony cracked Ultron, and it worked, and he went, 'Hey, whoever wants to retire and go home, can.' And then, the Illuminati came to rise behind the scenes, pulling the strings, but I think it's just a little bit of a better world for whatever reason, and Wanda was able to go and have the life that she deserved."
It had been originally theorized that the Ultrons in the "Illuminati" scene were created by John Krasinski's Reed Richards. Now, however, we know the robots were the work of everyone's favorite Billionaire Philanthropist.
Creating More Mythology Around the Ultron Incident
Something that stuck out for some about Age of Ultron when it came out was the short time span of Ultron's rampage. In the comics, the killer robot is an ever-present problem who's caused a great deal of trouble for Earth's Mightiest Heroes (and various other superheroes) on multiple occasions over the decades. In contrast, the film version of the villain existed for only a few days.
Since the movie's release, however, Marvel Studios has made efforts to give the 2015 sequel more weight. This began with Captain America: Civil War, whose premise centered around the aftermath of Age of Ultron, as Hulk's Sokovia incident sparked the world's desire to have superheroes working under the jurisdiction of different global governments.
Then, the House of Ideas took things a step further with What If...?'s eighth episode, "What If... Ultron Won?," which showed the dystopian future that would have occurred had Ultron not been stopped by the Avengers.
The story then continued (and concluded) with the show's Season 1 finale, "What If... the Watcher Broke His Oath?" The episode saw different super-powered beings banding together to stop Infinity Ultron — who had achieved a great level of power after obtaining the Infinity Stones — from ruling the multiverse.
Now, as revealed by Palmer, Multiverse of Madness is part of the tapestry of projects that have given more weight to the Avengers' second big-screen adventure.
Doctor Strange in the Multiverse of Madness is streaming on Disney+. The film will be available for purchase on 4K, Blu-ray and DVD on July 26, 2022. Avengers: Age of Ultron is also available to stream on Disney+, and for purchase on all home-media platforms.