Avengers: Doomsday theory: did Steve Rogers create Earth-828?

I think I've worked out the biggest mystery of Avengers: Doomsday. After seeing the Doomsday trailer at CinemaCon, my largest question was how Steve Rogers catches up with Thor and the other Marvel heroes in the present conflict. My theory is that Steve created the Fantastic Four's universe, Earth-828, by staying in the past at the end of Avengers: Endgame. If that's right, it also explains how the movie begins and why Doctor Doom has to be played by Robert Downey Jr.

It took me about three weeks after seeing the trailer to get there. Here is how I think it all connects, from the hammer moment on the ship to the face of the villain at the center of the story.

Steve Rogers returns to Thor in the Avengers: Doomsday trailer

The CinemaCon trailer, which hadn't been released publicly when I saw it, ends with Thor's speech wrapping up with "We're going to need a miracle" as he carries both Stormbreaker and Mjolnir on an unknown ship. Then we hear the voice of Steve Rogers say "Hey pal," and Thor says, "That's not possible." Mjolnir zips to Steve's hand. Steve looks down at the hammer and then smiles back at Thor. I can confirm that Johnny Storm is standing behind Steve on this vessel.

Steve looks different from how he appears in the first teaser from December. His look matches the leaked costume photos from January. His hair is longer, he has a beard, and he's wearing relatively modern clothes: a dark bomber jacket over a dark t-shirt.

So what is the miracle Thor refers to, and why does he consider Steve's return to be not possible? It's odd for Thor to say that. After Endgame, while standing on the Fantastic Four's ship, and as a god from another cosmic realm himself, it shouldn't shock the god of thunder to face quantum time travel and multiversal crossovers. I think Thor is saying "That's not possible" about something other than seeing Steve again, and I'll come back to that at the end of this piece.

How Pym Particles could have brought Steve Rogers back

There are a few straightforward answers to how Steve could have gone from the late '40s or early '50s of another universe to the present of whatever universe Thor is now in. To make the journey at the end of Endgame and return each Infinity Stone to its rightful point in history and the cosmos, Steve would have needed a large supply of Pym Particle vials to fuel each quantum jump.

We know he grabbed four additional vials from Pym's lab at Camp Lehigh in 1970. After the final battle of Endgame, Bruce Banner built a whole new quantum tunnel device, and Scott Lang and Hank Pym would have been on standby to help the Avengers produce as many vials as they needed for that return trip. Presumably Steve used the one extra vial meant to bring him back to the present to jump to 1949 and be with Peggy Carter instead.

But considering how close the Avengers came to catastrophe in the time heist by nearly running out of vials, I have to imagine they would have sent Steve on this last journey with a few contingency vials. So I think Steve could have used a vial and his quantum wrist tech to travel to wherever and whenever Doomsday is happening. There is, though, a more holistic explanation that I think explains everything.

The rumor that Steve Rogers lives on Earth-828

In recent months there have been rumors and speculation from scoopers claiming to know plot leaks, which I tried to avoid. They've pointed in a direction I'm no longer afraid to share, because it fits theories I now have evidence for and clues I've connected to the Doomsday trailer. The speculation is that at the beginning of Doomsday, Steve is in Earth-828, the Fantastic Four's universe.

I know I'm not the first to say or think this. I once wondered whether the TVA might relocate Steve and Peggy's entire house from whatever branch universe it was in to the 828 universe. Now I'm building on the speculation already out there: that when Steve stays in 1949, that world is the 828 universe of the Fantastic Four.

Robert Meyer Burnett, who I think also saw the Doomsday trailer in Las Vegas, tweeted, "Steve's appearance in the Doomsday trailer is 11 years after the clip posted here," referring to the December teaser. He added that in the Doomsday teaser, Steve has already met Doom because he'd been living on the Fantastic Four Earth with Peggy and his son. I don't know where Robert got the number 11. He is one of those people claiming insider knowledge, knowledge I don't have and can't independently verify.

Endgame's branch timeline rules and the Loki connection

Avengers: Endgame laid out its timeline logic through the Ancient One's explanation to Bruce Banner: when major changes are made to the past, like removing an Infinity Stone, a branch timeline forms, creating a new separate universe. This assumes the MCU treats timelines, universes and realities as the same thing.

That at least seems to be the case with the sacred timeline and its branches in the Loki series. I assume Doomsday will adopt that idea if it includes Loki and the TVA, and if it builds on what Renslayer tells Loki in the series pilot: "What they did was supposed to happen. You escaping was not."

The Russo brothers and Endgame's writers disagreed about Steve's choice

After Endgame, the Russo brothers said that when Steve stayed in the past, he created a new alternate branch history, separate from the history of the MCU. In their interpretation, Steve lived his life in some other universe, and at the end of that life, old Steve used multiverse navigating technology to return to Earth-616, hand Sam the shield, and coyly avoid talking about what his life had been like.

The screenwriters of Endgame, Christopher Markus and Stephen McFeely, had a different interpretation that contradicted the Russos at the time. They believed Steve stayed in the past of the main MCU timeline, that there was only one universe, and that Steve lived in the background of the history we'd been following.

I've always pointed out the logic problems with that version. It would mean Steve let his best friend Bucky Barnes be tortured for decades by Hydra, let JFK be assassinated, let Tony Stark's parents be murdered, and let 9/11 happen. Everything bad that followed would be Steve's fault, because he knew those things were coming and didn't stop them.

The big idea behind Doomsday could be Steve Rogers creating Doctor Doom's world

In 2025, the Russo brothers and returning writer Stephen McFeely mentioned in interviews a big idea that excited them about coming back for another Avengers movie. I think that idea had to do with their old disagreement: fixing and clarifying the logic of Steve's choice, and showing how that choice led to the consequence of Doctor Doom. Specifically, I think Steve created the whole 828 universe of the Fantastic Four, which is, for now, the one universe with Doctor Doom in it.

Imagine that the 828 universe is the branch Steve formed by staying in the past. That nexus moment would have created a branch history needing to fill in a hypothetical past and future around that new 1949. Presumably World War II played out the same way as in the 616 universe, so there would still be a Peggy Carter who missed and loved Steve. But with a super soldier Steve Rogers who never got frozen in the ice, still serving American interests in the D.C. area, the Cold War and the Hydra conspiracy wouldn't necessarily have played out the same way.

Steve could have made different choices throughout the 1950s. In 1949, around the time the Soviets tested their first atomic bomb, he could have gone to Robert Oppenheimer and Lewis Strauss at the Atomic Energy Commission and told them they didn't need to build the hydrogen bomb or have an arms race. I think this big idea was inspired in part by Robert Downey Jr. playing Lewis Strauss in a movie the Russos and McFeely saw.

I think Steve could have done about a decade's worth of timeline altering. By 1961 the world could look entirely different, with no NASA but ANSA instead, as we saw in Fantastic Four: First Steps (2025). That ANSA would have sent Reed Richards, Sue Storm, Johnny Storm and Ben Grimm into space, where cosmic radiation on a test flight gave them powers. Maybe the reason First Steps conveyed that radiation only through audio of a radio transmission is that those cosmic rays came from some incursion related side effect of what Steve did in this alternate Earth.

The Earth-828 timeline from 1949 to Doctor Doom

If this theory is correct, the 828 timeline starts in 1949, the year Steve stayed behind with Peggy. That date comes from the official Endgame screenplay, which places Peggy's house in Washington, D.C., in 1949, and it looks like the fall of that year. Then, in the mid '50s, Steve and Peggy's baby is born. Some time has passed between Endgame's final scene and the first Doomsday teaser. It takes at least nine months from conception to birth, and that baby is at least a few months old.

The motorcycle Steve rides is a 1950 Triumph T100, and it doesn't look new, at least a year old. So I'm putting that teaser scene at 1954, since Steve and Peggy would have wanted some honeymoon time and some dancing before starting a family. We've been guessing that they'll name their son James, Jim or Jimmy, after James Buchanan Barnes.

In 1961, the Fantastic Four arrive. Sue Storm creates the Future Foundation, which unites the world in peace, suggesting no Cold War with Russia and probably no Hydra in this universe. In 1965, the main events of First Steps take place, and Galactus shows up and gets teleported away. The post credits scene shows an animated kids show inspired by the heroes, seen by a father and son whose faces we don't see. Some have theorized that could be Steve and his son Jim, and I'm not the first to raise it. That boy would be around 11 years old.

That brings us to 1969 and 1970, when the mid credits scene of First Steps takes place and Doctor Doom arrives and takes Franklin Richards. That would be the point where the Fantastic Four connect with the other heroes in Doomsday. By my count that's closer to 15 or 16 years between the teaser scene with Steve's baby and Steve with Thor in the trailer. Maybe my math is wrong and it is something like 11 years. I don't know.

Why I think Steve Rogers starts Doomsday with the Fantastic Four

The big detail pointing me this way is Johnny Storm in the background on Steve and Thor's ship. I think the other members of the Fantastic Four are there too, and I think it's their ship, the one we see in the Thunderbolts post credits scene. Earlier in the trailer, when Thor leaves the Fantastic Four's ship at Avengers Tower, he's carrying only Stormbreaker, so I think that moment comes after the moment with Steve.

So even though we don't see him in the first 20 seconds of the trailer, when the Fantastic Four and Thor walk off that ship, I think Steve is with them. I also think Steve is in Avengers Tower with everyone else when Thor and Reed Richards explain what's going on. That tells us Steve must start the movie in the same universe as the Fantastic Four. The most logical explanation is that he starts the movie living in their world, a world I think his actions in Endgame spawned into existence.

In my version of Earth-828, Steve is a retired World War II super soldier who did enough to stop the hydrogen bomb from being invented in the early '50s and didn't need to be a hero after that, especially once the Fantastic Four arrived. He's ready for a quiet life as a father. Then Doctor Doom shows up and takes his kid, and Doom looks a lot like his old friend Tony. Steve goes to the heroes of this world who know about the multiverse, the Fantastic Four, who tell him their kid is missing too. Then Thor flies in through a rift in the sky, meets them in the Baxter Building and says his daughter is missing too.

When the Fantastic Four cast told Collider that many familiar Avengers faces would be on that couch with them in the redesigned Baxter Building lobby, I think they weren't only referring to Thor. I think they were referring to Steve Rogers.

Why Thor says "That's not possible" about Doctor Doom

When Thor says "That's not possible," I don't think he's only reacting to seeing Steve. I think he's talking about the most chilling consequence of what Steve did. The alternate 828 universe produced a villain the multiverse had previously denied existence: Victor Von Doom. And the Victor Von Doom of the 828 Latveria looks exactly like their old friend Tony Stark.

In every other universe of the sacred timeline that He Who Remains and Loki tried to maintain, someone that smart and that talented became Tony Stark. But in this accidental universe that never should have been created, someone with that soul became Victor Von Doom. Someone named Doom wearing Stark's face is what scares Thor this much, and it's what he considers impossible. That's how I think Steve returns in Doomsday, and how the ending of Endgame could be reinterpreted to connect the dots to the Fantastic Four, Doctor Doom and what's really happening in the film.