Avengers: Endgame brought into the MCU the use of time travel on a massive scale. The theatrical releases had already toyed with the concept when it came to Doctor Strange’s use of the Time Stone both in his solo outing and in Avengers: Infinity War, but it was only in 2019 that we got to see it put to proper use. When doing so, movies usually tend to detail the mechanics of the whole thing, forcing themselves into establishing strict ground rules in which they get to play around for a couple of hours, and Endgame wasn’t any different. But even that didn’t keep fans from theorizing around what could have truly happened in the movie and what it all meant for the future of the MCU. There was enough exposition in the movie to help people understand how it all worked, but even that didn’t stop people that were actually involved in the making of it to have very different opinions on what time travel in the MCU was really like.
In an interview with Fandango, writers Christopher Markus and Stephen McFeely were quoted saying:
We are not experts on time travel, but the Ancient One specifically states that when you take an Infinity Stone out of a timeline it creates a new timeline. So Steve going back and just being there would not create a new timeline.
And at the same time, co-director Joe Russo is on the record for saying:
Both Ancient One and Hulk were right. You can’t change the future by simply going back to the past. But it’s possible to create a different alternate future. It’s not a butterfly effect. Every decision you made in the past could potentially create a new timeline. For example, the old Cap at the end movie, he lived his married life in a different universe from the main one. He had to make another jump back to the main universe at the end to give the shield to Sam.
They can’t both be right. But instead of trying to figure out who’s right and who’s wrong based solely on their status in the making of the movie, let us focus on what should really matter: What does the movie tell us?
In this regard, the first key moment is the Banner and Rhodey discussion just before Clint test runs the quantum suits. It’s here that we find out that you can’t change your past even if you travel back in time. What you can do is relive past situations, that become intrinsically different just because of your presence. The time flow should therefore split, creating a new branch reality. This is all basically confirmed once we get to witness the team’s time travels. Even though they all try to stay out of sight while there, and considering some of their interactions don’t actually negate events we’ve known to have occurred in the MCU, several incidents simply cannot have happened on what we might now call the MCU’s Prime Timeline. And once that becomes obvious, you understand that this now applies to every timeline created, on every trip each member of the Avengers makes, since you cannot have different mechanics to essentially the same type of actions. So now, even the most innocuous interaction in a different time stream, should make for a slightly different future than the one we’ve known to have happened in the Infinity Saga.
So where might these new timelines take the MCU moving forward? The narrative opportunities coming from these new timelines are immense, with new characters rising, and not so new characters developing in new ways. You can now nullify the status quo that has been built through the years using these new timelines, launching into storylines that have become increasingly unlikely to occur in the Prime Timeline.
So, what realities could we find developing in the branches Avengers: Endgame created in the time flow? Let’s being with the first of these new timelines to ever be created:
CLINT TRAVELS BACK IN TIME TO HIS FAMILY FARM
This served as a simple test for the missions to come, so Clint didn’t have the time to impact this new timeline in any meaningful way. He took his kid’s baseball mitt back to 2023, and that’s about it. The Butterfly Effect might turn this into some world world-shattering event but that would be unlikely.
TONY, STEVE, BANNER, AND SCOTT TRAVEL BACK TO THE BATTLE OF NEW YORK
Steve’s interactions with Rumlow, Sitwell, and 2012’s Cap could probably all be accredited to 2012’s Loki impersonating him, making it easy to imagine the timeline wouldn’t be that impacted. What is not so easy to sweep under the rug is the fact that Loki got away with the Space Stone. The consequences are huge since now Thor isn’t able to take both his brother and the stone back to Asgard, directly influencing the events of Thor: The Dark World as well as everything that came after that.
THOR AND ROCKET TRAVEL BACK TO ASGARD
Thor and Rocket’s actions could actually fit into what we saw happening on Asgard in Thor: The Dark World. All it takes is for Frigga to have kept her conversation with her son to herself and continue on with her day as if it never took place. But since a new timeline was created, things could have evolved through a different path. Frigga didn’t want to hear what her son was about to tell her about her future, but who’s to know if she didn’t end up taking precautions after he left? Maybe she didn’t die that day. Maybe someone else did. This could be an interesting path going forward, making for a different Asgard that wouldn’t be so pervious to Hella a few years later, of that could maybe even allow for her showing up ahead of schedule. Ragnarok could turn out to have a very different outcome.
NAT, CLINT, RHODEY, AND NEBULA TRAVEL TO MORAG
Even if the Power Stone was to be returned in a way that allowed Quill to retrieve it as was saw in Guardians of the Galaxy, the events of that movie would still be impossible to replicate moving forward. Peter Quill would never meet Gamora since she left this timeline with Thanos and so the Guardians of the Galaxy would never come to be (at least the team we’ve come to know). And with 2014’s Thanos traveling to 2023 and dying there, this timeline wouldn’t have the Mad Titan pulling the strings, orchestrating his future pursuit of the Infinity Stones. This would mean that Xandar wouldn’t be destroyed and that the entirety of the Nova Corps would still be alive. The ramifications of Thanos going missing could be felt on even on earth because, without the events of Avengers: Infinity War, the Avengers would never get back together the way they did after the events of Captain America: Civil War, amongst other things.
TONY AND STEVE TRAVEL TO CAMP LEHIGH
In the new timeline, Steve stealing the Pym Particle vials from Hank’s lab, could make Pym even more paranoid than he was when it came to the way S.H.I.E.L.D. tried to control his genius and intrude into his research. This could expedite him leaving the organization, all but making sure Janet van Dyne wouldn’t disappear after going sub-atomic on a mission in the ’80s.
Also, maybe Howard Stark became a more present father after that conversation with Tony. The “No amount of money ever bought a second of time.” that Howard once passed on to his son, and that was now said by Tony back to his dad, could help to mold a different version of Howard, that could eventually give a young Tony a different childhood. And that could end up being what makes him not becoming Iron Man down the line. Perhaps he wouldn’t use B.A.R.F. in the way he did, and that piece of technology wouldn’t get the name he gave it. Quentin Beck would have fewer reasons to hate Tony and the idea of Mysterio wouldn’t come to fruition allowing Peter Parker to enjoy a nice little trip to Europe with his friends like he always wanted.
STEVE GOES BACK TO PEGGY
There was a line spoken by Banner, just after Steve left and didn’t return to 2023 as scheduled, which made it absolutely clear that Cap had indeed spent his entire life, not on the same timeline he had left behind.
Sam: Where is he?
Banner: I don’t know, he blew right by his timestamp. He should be here.
This would mean Steve went beyond Banner’s present, having had to travel back in time to 2023, to the moment he knew his friends would be there, by the lake. This also shows us that, since Steve went back to 1949 to be with Peggy and not to mess with the Infinity Stones, that you don’t need to remove one of them to create a new time stream. What the Ancient One told Hulk back in 2013 was that by removing a stone, that reality would be left in disarray, for being unbalanced. Once Banner said he’d make sure the stones would be returned, that reality would still continue to exist, just not shrouded in darkness.
And so, since Captain America crashed into the Arctic sometime in 1945, so this would mean that, from 1949 onwards, there would be two Steve Rogers in this new timeline. One living his best life besides Peggy Carter, the other frozen inside a Nazi aircraft until being found several decades later.
Knowing what major events the future would bring, 2023’s Steve would have the possibility to try to prevent whatever he felt should be prevented. And it’s then only natural that the more he tampered with this new timeline, the more it diverged from his own. Being this, as far as we know, the furthest back someone traveled back in time, this is the timeline that could make for a more distinct 2023. The possibilities are too many to even consider.
So this is where the MCU stands at the moment. At least seven active timelines in constant evolution, and even though we are focused on the Prime Timeline for the foreseeable future, there is nothing stopping characters from the other ones from dropping by for a visit. Marvel already teased the possibility of a character being from another earth in Spider-Man: Far From Home, it’s only a matter of time they do it for real. Maybe sooner than we realize.