Marvel’s Avengers: Endgame left a major question unanswered: How did old Steve Rogers return to the original Marvel Cinematic Universe timeline? At the end of Avengers: Endgame, Steve Rogers used Pym particles to travel through the Quantum Realm and time to return all the Infinity Stones to their original places in the timeline.
But instead of going back to the present, he decided to stay in the past and live his life with Peggy Carter.
The final scene of Avengers: Endgame shows Steve finally dancing with Peggy, fulfilling the promise he made to her in Captain America: The First Avenger.
This moment represents Steve being done with making sacrifices for others and choosing to live for himself for once—an opposite ending to Tony Stark’s as Iron Man, where the selfish billionaire sacrificed himself to defeat Thanos. However, the film leaves one question unanswered: it doesn’t explain how Steve returned to the present MCU timeline.
The Russos Explained Steve Rogers’ Reappearance In Endgame
To understand how old Captain America might have come back from the past, it’s important to know exactly where he was. Unfortunately, the people telling Steve Rogers’ story don’t all agree on this.
Directors Joe and Anthony Russo, who worked on Avengers: Endgame, have said they think Steve created a branch in the timeline when he stayed in the past.
If this is true, it means that if Steve wanted to return to the main MCU timeline, he would need to travel between timelines, not just go backward or forward in the main timeline. But it’s unclear if the Pym suits and particles could travel from a branched timeline to the main timeline.
Another issue with this explanation is the introduction of the Time Variance Authority in MCU Phase 4. If Steve did create a branched timeline, the TVA would probably have interfered, either getting rid of him or putting him back in his original time.
What Happened To The Old Captain America? How Did He Come Back?So, if Steve was living in a branched timeline, Marvel would need to explain how he could travel from that timeline to the main MCU timeline and why the TVA allowed that branched timeline to exist.
The ending of Loki season 2 might offer a rough explanation for why that timeline could continue, potentially fixing the issue with old Captain America’s return if this idea is correct. But this doesn’t directly address the detail of how he came back, leaving the explanation unclear.
However, the Russos’ idea is different from what the writers, Christopher Markus and Stephen McFeely, think. They argue that Steve stayed in the main MCU timeline and his decision to stay in the past didn’t create a branched timeline because he was always meant to be there.
This explanation solves the issue of the branched reality and gives a possible answer for how old Captain America appeared at the end of Avengers: Endgame.
Endgame’s Ending Still Has A Major Unanswered Mystery
If the Russos are right and Steve created a branched timeline where he lived out his life with Peggy separate from the main MCU timeline, he’d need a way to get back. Since it’s a different timeline that doesn’t have Captain America as part of the Avengers, it’s likely they never developed the technology he would need to return.
What Happened To The Old Captain America? How Did He Come Back?Or, if they did, it might have been different in a way that made it impossible for him to come back.
But if Steve could still use the suit and Pym particles that helped him put the Infinity Stones back, it’s unclear how he could’ve returned without the platform, since there may not have been one in the branched timeline, and there was only one in the main timeline.
It makes more sense for the Russos to be wrong about Steve creating a branched reality and instead say that he stayed in the MCU timeline. In this case, he could simply wait without needing to time travel or travel between timelines. Of course, he’d have to sneak over to the bench while Sam, Bucky, and the Hulk weren’t looking, but that seems more possible than the other ideas.
Still, all of this is just guesswork based on what’s shown in the movie and the different opinions from the filmmakers about what happened to Steve. The MCU hasn’t explained in canon how old Captain America returned to the main MCU timeline to give the shield to Sam.
Whether it’s explained in Captain America: Brave New World, Thunderbolts, Avengers: The Kang Dynasty, or Avengers: Secret Wars, Marvel needs to clearly solve this last Avengers: Endgame mystery and clear up all the confusion about how old Captain America returned.