Marvel’s Loki: Making Sense of the MCU’s Time Travel Rules

At first glance, the time travel rules in Loki seem at odds with the Avengers: Endgame time heist. But is that really the case?

Loki (Tom Hiddleston) arrives at the TVA in Loki (2021)
Photo: Marvel

This article contains spoilers for Loki episode 1, Avengers: Endgame, and perhaps the very fabric of reality itself.

Nobody said time travel was easy. When Marvel Studios officially introduced temporal shenanigans into its cinematic canon in Avengers: Endgame, it did so with noble intentions. Our Avengers had to save the universe and recapture the 50% of the population that Thanos dusted away. The easiest way to do so was with a dash of Pym particles and an entanglement within the Quantum Realm. 

Unfortunately, however, engaging with time travel means engaging with its rules. Now that the studio’s third Disney+ series Loki has brought the God of Mischief into contact with the Time Variance Authority and the Time Keepers’ Sacred Timeline, the Marvel Cinematic Universe faces the unenviable task of making sense of the impossible.

Through one episode, Loki has done a solid job of explaining the rules and stakes of time travel as it applies to Loki, itself. Still, some questions remain about how the rules of time established in Loki apply to Avengers: Endgame’s time heist and the rest of the MCU at large. For a proper example, take a look at these very astute questions raised by Brit in the comment section of our Loki Episode 1 Easter eggs article

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“Please can we have a Q&A article on this. Aren’t there already two timelines? One with Steve Rogers in the Avengers and one where he stayed in Peggy? (Editor’s Note: Phrasing) And a third where Thanos left? Either way, aren’t there already multiple? And shouldn’t Steve Rogers be classed as a variant as he went rogue?”

The simple answer to all of these questions is that, despite its interconnected nature, the Marvel Cinematic Universe is made up of individual films (and now TV shows) written by individual writers. So the events of Avengers: Endgame may not make perfect canonical sense in Loki. We know for a fact that Loki’s TVA adventure was not conceived of until Avengers: Endgame had already been written by Christopher Markus and Stephen McFeely. In an interview with EW, Marvel head Kevin Feige revealed that Loki stealing the Tesseract was never designed to lead into another time travel story.

“[That scene] was really more of a wrinkle so that one of the missions that the Avengers went on in Endgame could get screwed up and not go well, which is what required Cap and Tony to go further back in time to the ’70s,” Feige said.

If the time travel rules of Loki are to be consistent with the time travel rules of Avengers: Endgame it will be only because the later show retrofitted itself to work within them. For what it’s worth, Loki head writer Michael Waldron (who previously wrote for the timey wimey Rick and Morty) claims that the show’s approach to time travel rules are bulletproof.

“I was always very acutely aware of the fact that there’s a week between each of our episodes and these fans are going to do exactly what I would do, which is pick this apart. We wanted to create a time-travel logic that was so airtight it could sustain over six hours. There’s some time-travel sci-fi concepts here that I’m eager for my Rick and Morty colleagues to see,” Waldron told Vanity Fair.

In that same interview, Waldron notes that Avengers: Endgame presents the rules of time travel as The Avengers understand them. Perhaps this means that Loki will correct the Avengers in some areas and clarify the rules in future episodes. If that’s the case, Loki will have a lot of work to do. As we understand all the rules now, the time travel of Endgame does appear to be at odds with the time travel of Loki in several respects.

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Hopefully, the show will explain away those inconsistencies. In case it doesn’t, however, let’s try to do it ourselves. 

Why Were the Events of Endgame Sanctioned?

Thanks to Loki episode 1 “Glorious Purpose” we have one bit of useful canonical information when it comes to the time travel in Avengers: Endgame. When Loki stands trial for his timecrimes, he tries to pass blame onto the Avengers. But the judge presiding over his case, Ravonna Renslayer (Gugu Mbatha-Raw), tells Loki that everything the Avengers did was supposed to happen

How can that be the case though? Just about everything that The Avengers did appears to fly in the face of the Time Keepers’ mission of maintaining the Sacred Timeline. Tony and Steve’s team sent no fewer than 11 individuals back in time to three distinct time periods. They then removed sacred objects from those time streams, brought them back to the present, used them, then returned them to their appropriate locations in time. How on Earth did that not create dozens if not hundreds of new timelines that threaten the singular supremacy of the Sacred Timeline?

I’ve got two potential explanations for that, both of which are imperfect and flawed. But absent further information from Loki, they might be the best we can do for now. 

The first option is that perhaps the TVA is oversimplifying how neat and tidy the Sacred Timeline looks. Within the TVA offices, the visual representation of the Sacred Timeline is a single straight line on their computer monitors, with potentially dangerous new timelines being represented by jagged fresh lines branching off from the main line. While this is a helpful visual for the TVA office drones to keep an eye on things, it might not represent the full reality of the Sacred Timeline.

The Sacred Timeline may be a gnarled, ugly beast with one long branch spreading out into infinity and smaller twigs doubling back on themselves along the big branch. This would mean that it’s possible for time travel within the Sacred Timeline as long as it’s occurring on the Sacred’s Timeline main branch and with the Time Keepers’ blessing. Why would the Time Keepers sanction some time travels and deem others as unacceptable Nexus events? That’s anyone’s guess. 

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The other possibility comes from a theory within Endgame itself. The closest that Marvel’s Infinity Saga conclusion gets to addressing the “rules” of time travel is via a conversation among Scott Lang, James “Rhodey” Rhodes, and Bruce Banner. All three men have their opinions on time travel, but the film gives Bruce the final word, subtly suggesting that it’s his interpretation that’s correct. Here is what he has to say:

“Time doesn’t work that way. Changing the past doesn’t change the future. Think about it, 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.”

Let’s call this the Subjective Theory of MCU Time Travel. A certain kind of time travel is allowed and effective as long as the time traveller understands that the nature of time comes down to their subjective experience of it. Bruce Banner can’t create a new timeline when traveling to the past because he’s aware that the past is now a part of his own subjective future. As long as his story ends up where it’s supposed to be, which is to say activating the Infinity Gauntlet in 2023, then everything will be ok.

And that brings us to a certain time traveling lothario…

Why Didn’t Steve Rogers Create A New Timeline?

The idea that Steve Rogers didn’t create a new, unsanctioned timeline by living out an entirely new life with his lost love Peggy Carter is truly baffling. If Loki can create a Nexus event by picking up the Tesseract, how can Steve Rogers abandoning Captaining America in favor of smooching Peggy for 50+ years not?

Well, maybe we can make sense of this by combining our two theories above. For starters, the Sacred Timeline has to accommodate for other smaller, sanctioned timelines within itself – it just has to! Any decision you do or do not make creates new possibilities and new universes. When you choose to wear a blue shirt in the morning as opposed to a red shirt, you are creating an entirely new unseen universe in which you wore that red shirt (and probably won the lottery or something, I don’t know).

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Going back to that gnarled branch analogy from before: perhaps the Sacred Timeline isn’t so much of a single line but a series of lines contained within a larger line – fiber optic cable-style. Steve Rogers going back in time and living out a new life is just part of one of the smaller, sanctioned lines clinging onto the main one.

There’s also the reality that Steve did what he was required to do at the end of the day. Having delivered all of the Stones back to their respective places he returned to the present an aged man (and looking like Joe Biden). He then presumably passed away peacefully of natural causes in the timeline that he was supposed to die in at the precisely correct point. 

That new past was Steve’s future like Bruce said it would be. Therefore it affected only him. What of all the people Steve interacted with in his new life though? It’s possible that they just dissipated away once Steve returned to the present or their lives carried on normally inside a pocket universe contained within the Sacred Timeline. There’s also a darker possibility that the TVA had to go in and liquidate that whole timeline once Steve had exited it. Sharp-eyed viewers have spotted what looks to be Peggy Carter in Variant prison garb in the background of Loki’s first episode.

That would be a pretty upsetting conclusion to Steve and Peggy’s character arcs, but it would resolve the temporal headaches created by his time travels in the ruthlessly unsentimental way that only the TVA can pull off.

Why Are Variants Allowed on the Sacred Timeline? 

At the conclusion of Avengers: Endgame, there is at least one Variant from a separate timeline existing within the Sacred Timeline. That is, of course, the Guardians of the Galaxy’s Gamora. Thanks to the Avengers’ meddling, she arrived in the Sacred Timeline alongside Variant versions of her “father” Thanos and her “sister” Nebula. Variant Thanos and Variant Nebula are eventually dispatched by the Avengers but Gamora remains behind as a curious sideways world version of herself in a new reality. How is this allowed?

The answer to this is a very well-reasoned “because the Time Keepers said so.” As far as we understand it, the Time Keepers only goal is to maintain the sanctity of the Sacred Timeline. If that means bringing in reinforcements from other timelines, then so be it.

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But wait a minute, Alec, you just said “other timelines.” How could Variant versions of Thanos and Gamora even exist on a separate timeline to join the Sacred Timeline if the TVA is so adamant on stamping out other timelines? I don’t know, man. My head hurts. It likely goes back once again to that “big branch” or “fiber optic” cable analogy though. It’s quite simply not possible for there to not be alternate timelines once time travel comes into play. So those timelines have to exist as appropriate branches attached to the main branch. Those Variant Gamoras, Nebulas, and Thanos were therefore never Variants to begin with. They were merely different aspects of the same character from different parts of the same timeline.

Is this all complicated? Yep. Does it  make perfect sense to me? Absolutely not. That doesn’t change the fact, however, that there is one unshakable tenet of the Marvel Cinematic Universe canon when it comes to time travel now thanks to Loki. And that’s that the events of Avengers: Endgame happened exactly as the time stream needed them to. Steve Rogers, Tony Stark, Bruce Banner, Natasha Romanoff, and company are not Variants. No one went “rogue.” That reality makes it harder to fully understand and explain away why dozens of Nexus events weren’t created by their actions. But explain it away we must, because the Time Keepers say so.

Loki airs new episodes Wednesdays on Disney+.