How Avengers: Endgame Blows the MCU Timeline Wide Open

Mike Delaney

SPOILER WARNING: The following article contains MAJOR SPOILERS for Avengers: Endgame. Proceed at your own risk.

Time Travel: An Idiot’s Guide

As we now know – and long suspected from set photos and leaks – Avengers: Endgame relies heavily on the concept of time travel. At the beginning of the film, Thanos destroys the Infinity Stones. Five years after the Snap, the remaining Avengers figure out how to time travel using the Quantum Realm and pull off a Time Heist. They snag the Infinity Stones from various points in history in order to reverse the Snap and bring everyone back to life.

That’s the simple explanation, anyway. The mechanics of time travel are a little more complex. As Endgame reveals, their version of time travel is not like Back to the Future. Or Star Trek. Or Terminator. Or even Hot Tub Time Machine. Changing something in the past will not affect the future. As Bruce Banner explains; “If you travel to the past, that past becomes your future, and your former present becomes the past which can’t now be changed by your new future.”

Okay, sounds simple enough. No matter what you do in the past, the future you left stays unchanged. Seems a bit of a rigid rule, though. But, as we learn later on, that doesn’t mean you cannot affect changes in the past. Just that they do not affect the future of the person affecting the change.

While trying to acquire the Time Stone, Bruce encounters the Ancient One defending the New York Sanctum during the Chitauri invasion in 2012. She tells Bruce that the Infinity Stones create the flow of time and removing one from the timeline creates an alternate reality. In essence, for every stone that is removed from history and taken to 2023, a new alternate reality is created. However, as Bruce states, returning the stones to the point where they were removed would erase those alternate realities since from the point of view of the universe, the stones were never really gone in the first place.

Simply put, if the heroes from Endgame were to go back to the Battle of Wakanda in Avengers: Infinity War and kill Thanos before the Snap, it would not affect their reality. For them, the Snap happened and that cannot be changed for them. However, killing Thanos before the Snap would result in an alternate reality where it never occurred.

The main MCU is still the canon of films released over the last eleven years but now, thanks to the events of Endgame, there are now several alternate realities that different versions of our heroes are now experiencing because certain events occurred that could not be fixed as easily as returning the Infinity Stones to the point they left the timeline.

So There Are Two MCUs Now, Right?

Well no, but actually yes. There’s probably more than two, in fact. Whether or not we get to see them is another matter though. The events of the Prime MCU are the main canon and presumably the reality in which all future films will be set to avoid confusion. So, for the purposes of the film universe, there is still only “one” MCU. The Russo Brothers have even confirmed that there is at least one major alternate reality out there – the one that Steve Rogers spent the rest of his life in after returning the Infinity Stones to the past.

Writers Christopher Markus and Stephen McFeely might view that differently, telling Fandango they believe it’s the Infinity Stones involvement that leads to branching timelines,  but we’re convinced by the overwhelming majority of evidence that says alternate realities created ‘simply’ by tinkering with time — regardless of whether an Infinity Stone is involved — are now out there. Plus, they stress, it’s just a theory and they’re not experts on time travel. So there.

“If Cap were to go back into the past and live there, he would create a branched reality. The question then becomes, how is he back in this reality to give the shield away?” — Avengers: Endgame co-director, Joe Russo

So with this confirmation that alternate realities can exist due to a change in the timeline, like the addition of a person, then it stands to reason that there are now at least four distinct MCU universes. The main one is the Prime MCU plus realities created by three major timeline changes seen throughout the course of Endgame.

Captain America’s Happily Ever After

At the close of the movie, Captain America takes the six Infinity Stones (and Mjolnir) back to the points in history where they were acquired from. The trip should take seconds from the point of view of Bruce, Bucky, and Sam. But when Steve doesn’t return, it is clear something else has happened. As it turns out, Steve decided to stay in the past and finally got to dance with Peggy. He reappears in the same spot as an elderly man having lived a full life.

So does that mean that there were two Caps in the MCU all this time? Well, yes and no. Bypassing Markus and McFeely’s theorising, the Russo Brothers have already addressed this issue. By remaining in the past, Steve created an alternate reality, according to the Endgame directors, and that’s the one he lived in with Peggy. This is a more palatable and more interesting notion than the idea that there were two Steve Rogers in the Prime universe, one who remained hidden despite knowing everything that was to come. If Prime Steve was in an alternate reality, then he could have changed a lot of things to make the universe a better one than the one he came from, especially if the point of divergence was decades before the events of the MCU.

“We [Christopher Markus and I] took the job knowing it would be the biggest puzzle we had ever faced, and really few people had ever faced. It’s crazy.” — Avengers: Endgame co-writer Stephen McFeely on tackling the biggest series finale ever

At the close of Endgame, Steve returned to the Prime universe to give Sam the Captain America shield and pass on the mantle to him. Which raises the question – where did the shield come from? The Prime universe Captain America’s shield was heavily damaged in the final battle against Thanos, and Steve didn’t take another version of it into the past with him. The implication is that the shield is from the other reality. So what happened to the Captain America of that universe?

Thanos Disappearing Screws With The Timeline Royally

Rhodey and Nebula time travel to 2014 to grab the Power Stone on Morag shortly before Peter Quill finds it during the events that will kick off Guardians of the Galaxy. During the mission, thanks to some quantum entanglement technobabble due to having two Nebulas in the same time period, the Thanos from 2014 learns about their plan and his eventual victory four years before it happens. After capturing the Nebula from 2023 and replacing her with Nebula 2014, Thanos travels forward in time (by reverse engineering Nebula 2023’s tech) to 2023 with his entire army. This sets up the entire final glorious battle of Endgame which ends with him and his forces being dusted — at the cost of Tony Stark’s life.

Thanos and his army’s removal from the timeline creates an entirely new alternate reality since it cannot be repaired. There is no Thanos and company to reinsert into the timeline to ensure events proceed as they once did. In this reality, the events of Guardians of the Galaxy cannot move forward as they originally did.

There might be similarities, such as Ronan attacking Xandar Prime, but there would be major differences. Gamora and Nebula are no longer present, for a start. While Quill, Groot and Rocket might all eventually end up in the Kyln, there is no reason for Drax to join up with them since his entire interest in them was built around trying to kill Gamora and eventually Ronan. Gamora was also responsible for directing them to the Collector, so events surrounding the acquisition of the Power Stone would play out very differently.

“Occasionally something will slip through the cracks that screws it up, and you’re like: “No, no, no, no, no”. It’s too late, it’s been released.” — Avengers: Endgame co-writer Christopher Markus tells Fandom keeping an eye on timeline continuity in the MCU isn’t easy

Thanos’s removal from the timeline also means that this reality does not have to deal with his quest for the Infinity Stones or his invasion of Earth in 2018. This is a reality where the Snap never occurred and everyone – including Vision, Black Widow and Iron Man – are all still very much alive.

Loki Being a Sneaky Devil

During the 2012 sequence of the Time Heist, Loki ends up getting hold of the Tesseract and teleporting away, something that presumably did not happen in the Prime timeline. This sets up another timeline where Loki is free after the events of Avengers and running around with the Tesseract. In the Prime timeline, he is taken to prison on Asgard where he begins his redemption arc. Without that occurrence, what kind of villain would Loki end up becoming? With the Tesseract in his possession, would Loki join up with the Thanos of that reality sooner? Or would he use the power for himself to take over Asgard openly and not by underhandedly replacing and impersonating Odin?

“Maybe I’m speaking for others but maybe not killing Loki would have been exciting for some people.” — Endgame co-director Anthony Russo on what he’d go back in time and change in the MCU if he could.

Of course, Loki’s escape is the biggest clue we have as to how the recently announced Loki television series will play out. Most of Loki’s interactions have been with his brother, Thor, but removing himself from the God of Thunder’s presence allows the storytellers of the Loki series a lot of room to craft a unique narrative where he can hopefully live up to the moniker of the God of Mischief.

Loki’s disappearance from Stark Tower in 2012 is not the only major change to the timeline. During the sequence, Steve Rogers uses his knowledge of the future to obtain the Mind Stone from Brock Rumlow and Jasper Sitwell by posing as a HYDRA agent. It is a glorious double callback and subversion to the iconic lift fight in Captain America: Winter Soldier and the recent “Secret Empire” comic series (in which Captain America is seemingly a HYDRA agent).

But how does Cap seemingly revealing himself as a HYDRA agent play out in the new timeline? Does HYDRA get exposed sooner in this reality after either Rumlow or Sitwell try to bring him more into HYDRA’s plans?

There is a possible explanation if the Captain America of 2012 reports his fight with his future self, whom he believes to be the escaped Loki. If HYDRA became aware of that, they might rationalize that the Captain America who exposed himself as a HYDRA agent was actually Loki in disguise. But bringing up the fight causes another slight issue – this Cap has just been told that Bucky is still alive. Will Cap believe that considering he thinks that he is fighting Loki? Given Loki’s trickster nature, it is possible that the other minor wrinkles in this reality could be explained away as his interference.

Far From Home

Spider-Man: Far From Home is the true end of the MCU’s Phase 3, and is likely to be the ‘breather episode’ after the heavy toll that Endgame took on everyone. A lighthearted adventure romp with an ebullient Spider-Man that everyone needs to cleanse the palate after Endgame. Spider-Man sorbet, anyone?

But the implications for the film following Endgame are just short of disturbing. Unless Far From Home is a prequel to Infinity War, then everything in the film happens in 2023. And Sony boss Amy Pascal revealed to Fandom some time ago that Spider-Man: Far From Home, indeed, picks up minutes after Endgame wraps as a story, with Joe Russo confirming this recently in a Q&A with a Chinese website. That means that in addition to Peter Parker and Ned Leeds, a large number of named characters in his class (MJ, Flash Thompson, Betty Brant, and Abe Brown at least) at Midtown High were dusted in the Snap. The odds of that are as unlikely as all six of the original Avengers surviving the original Snap … oh, wait they did. Either way though, that’s a hell of a thing to deal with when you realize some of your classmates are five years old than you now.

Of course, with Spider-Man: Far From Home being co-produced by Sony, there is a slim chance that they will not address the timeline issue at all, despite Joe Russo responding to a question he was asked in the interview with the Chinese website using Spider-Man’s reunion with Ned as an example. However, considering that Nick Fury and Happy Hogan are in the film, not addressing the recent death of Spider-Man’s mentor, Iron Man, wouldn’t be satisfying at all. Also, given the emotional depth of the relationship between the two characters, having Peter Parker unaffected by the events of Endgame would be a disservice to the audience as well. Peter’s reactions to Tony’s sacrifice should serve as the coda to Phase 3; in essence, as Spider-Man mourns, so do we.

Soul Stone

One of the bigger moments of Endgame is Black Widow sacrificing herself to obtain the Soul Stone from Vormir. As with Gamora previously, Black Widow’s sacrifice is permanent and cannot be undone by reversing the Snap. Bruce tries to bring her back when he uses the Infinity Stones but is unsuccessful. So what happens when Steve returns the Soul Stone to Vormir?

Assuming that the sacrifice is permanent, then returning the Soul Stone would still not bring Natasha back since Cap would have to return the Stone after her death. The Russo Brothers state that the Red Skull would probably return the Soul Stone to its location and wait for the next individual seeking its power. There would be no confrontation between Cap and the Red Skull because he is no longer the same person he once was and guarding the Stone is now his duty.

However, this is contradictory to what the Russo Brothers stated after Infinity War – namely that Thanos taking the Soul Stone from Vormir freed the Red Skull from his duty. So by that logic, Red Skull was freed from his duty when Black Widow sacrifices herself and should not be there when Steve returns the Stone. The act of returning the Stone to the exact moment it left the timeline might mean that Red Skull doesn’t have time to pack up and leave, though.

With the upcoming Black Widow film, perhaps the Russo Brothers’ comments are a smokescreen designed to not give away a potential plot point. What if the Red Skull was released from his duty, but there was still someone on Vormir to return the Soul Stone to? Could Black Widow become the new Stonekeeper and the Russos are intentionally misdirecting us to keep a potential plot under wraps?

In Conclusion

The big takeaway from the entire time travel plot device in Endgame is that there are now multiple MCU realities, and per the Russo Brothers’ comments that Captain America returned to the Prime timeline at the end of the film, there is a way to travel between them. So what does that allow for storywise? Quite simply, anything! If Sony’s Spider-Man movies are indeed taking place in the “same reality” according to both Amy Pascal and Kevin Feige, that includes the recent Into the Spider-Verse, which pre-dates Endgame in playing with the concept of alternate realities, exploring more possibilities. That film’s directors spoke to Fandom about Spider-Verse‘s connection to the MCU here.

As we discussed, Loki disappearing from Stark Tower during the Time Heist created a new alternate reality already. If Cap can figure out how to travel between the realities to pass the torch to Sam, then Loki should be able to figure out how to jump realities as well. Disney+ has announced a slate of shows, some of which deal with alternate timelines in their What If series, and others that star dead characters such as Loki and Vision. Endgame might be the end of the current incarnation of the MCU, but it has created a larger universe of possibilities as well.

Mike Delaney
Mike Delaney is Content Team Lead for Fandom's Movie/TV Vertical and specialises in all forms of entertainment. Star Wars fan and general pop culture addict. Only two beverages worth drinking are tea and whiskey.