In Endgame, the Avengers defeat 2014 Thanos from one alternate dimension, but since its a multiverse, wouldn't there be basically an infinite amount of universes where Thanos lives and the events play out like they did in Infinity War?
Technically Avengers Endgame does not get itself entwined with the multiverse/alternate realities/dimensions nightmare, instead it only plays with the even messier time-travel conundrum instead.
The jolly giant green scientist states;
You can’t just go back in time and change the past in order to alter the future. Because the future is already your past! You can’t change the future, because if you did, you wouldn’t be the same version of yourself who time-travelled in the first place to make that change.
So if we accept his reasoning, (I wont be arguing with him), there was only one Thanos.
Now for the crazy dance steps; Dr Strange did use the time stone to run 14,000,605 scenarios of which only one outcome would end in their favour, so it can be argued, (again I will not argue with the Hulk), that there are potentially another 14,000,604 alternate timelines that exist. However we can never experience such variations as each time we go back to see those potential alternatives our past doesn't change and any thing we experience is now our future.
Wow this sort of thinking just ties me in knots and makes me realise just how little sleep I have had within the last 3 days and the only thing I am certain of is that I will never disagree with the Hulk.
In Avengers: Infinity War, Dr. Strange has this conversations with Tony:
Strange: I went forward in time to view alternate futures. To see all the possible outcomes of the coming conflict.
Tony: How many did you see?
Strange: 14 million
Tony: How many did we win?
All of the futures are the various timelines that you are referring to. Here's an extract from what the Russo Brothers have mentioned. To them, futures, realities and timelines appear to be the same thing.
Anthony Russo: "Loki could absolutely still be alive in an alternate timeline."
Anthoy Russo: "In the movie, the Hulk is very explicit about what our rules are, which is you cannot change the present by altering the past. All you can do by going to the past — and for a character like Captain America, living in the past — is create an alternate future. So this is a world in which alternate timelines exist."
Joe Russo: "The minute that Loki does something as dramatic as take the Space Stone, he creates a branched reality."
Only a hand few are created because of the time-travel we see in Endgame, others could have been because of a whole bunch of reasons (like different choices) which are not discussed in the movie.
So, YES, are there many Thanos in various timelines that causes this infinity gem conflict. 14,000,605 timelines where this conflict occurs, to be exact. And the 1 timeline that is able to win is the timeline we get to see as part of the movie Avengers Endgame. The others don't get their second chance.
Other answers have explained the perils of telling a story involving multiple timelines-- if you're not careful, you end up with the idea that choice is meaningless and any victory is hollow.
What I want to do instead is suggest a way to interpret the movie's view of time travel so that the heroes' victory does have meaning.
Bruce Banner tells us that using the quantum tunnel to travel to the past creates an alternate timeline. That's why the Avengers don't need to worry about creating a paradox by changing their own pasts when they embark on the "Time Heist." 2023 Captain America can have a battle with 2012 Captain America, but that doesn't change his memory of events as they happened 11 years ago, because he's now in a new timeline.
Here's a crucial point, without which the story falls apart: The Time Stone doesn't have the same rules as the quantum tunnel. Most importantly, proper use of the Time Stone does not create alternate timelines. The Time Stone seems to be more like a rewind/fast-forward control for the timeline you're currently in, allowing the bearer to undo and redo history.
But didn't Doctor Strange use the Time Stone to visit alternate timelines in Infinity War? This is what he said:
I went forward in time to view alternate futures. To see all the possible outcomes of the coming conflict.
The Time Stone gave Strange the ability to see "possible outcomes," and he looked at 14,000,605 of them, finding only one where the Avengers won. If we treat these losing outcomes as alternate timelines, existing in the same way that the timelines accessible by the quantum tunnel exist, then the movie loses its meaning. We might have seen the Avengers triumph, but there are 14,000,604 Thanoses out there somewhere who won the battle. That's an overwhelming victory for the big purple guy, not something worth celebrating at all.
So, I argue that these "possible outcomes" don't exist as anything other than hypotheticals. Doctor Strange is not time traveling when he uses the Time Stone; he is just peering ahead at a future that is still uncertain to see all of the ways it could possibly go. By doing this, Strange was able to ensure that the "1 in 14,000,605" chance was the one that ended up happening-- the only one that ended up happening.
This applies to the other times the Time Stone has been used to alter the flow of time. Strange was not spinning off countless timelines by playing with the apple or restoring the Book of Cagliostro. There isn't a timeline where Wong remains dead or one where Dormammu claimed Earth. And there isn't a timeline where Thanos stands around awkwardly because Scarlet Witch destroyed the Mind Stone before he could claim it. When you use the Time Stone, you change your own timeline; you don't make a new one.
Okay, so what about the quantum tunnel, then? How many timelines did that create?
-- Scott Lang's initial jump five years into the future did not create a new timeline; it just skipped him ahead in the current one. How do I know this? Because Lang emerged in a world where he had been missing for five years. Compare this to Thanos's trip into the future later, where he entered a timeline that already had its own Thanos.
-- The test runs that "pushed time through Scott" rather than pushing Scott through time were failures, so no new timelines were created there.
Hawkeye's test run created a new timeline where he appeared in Iowa for a few minutes and took his son's baseball mitt. It seems unlikely that this timeline ended up significantly different from the original one.
There's a timeline created by the trip to 2012 where Hydra thinks Captain America works for them, Captain America fought a duplicate of himself, and Loki escaped with the Tesseract.
There's a timeline created by the trip to 2013 where Thor had a conversation with his mother and Rocket was chased through the halls of Asgard after stealing the Aether.
There's a timeline created by the trip to 2014 where Star-Lord was knocked out in the middle of his dance on Morag. The Thanos, Nebula, and Gamora of this timeline left it to travel to 2023 in the "main" timeline after finding out about the Avengers' time-travel shenanigans.
There's a timeline created by the trip to 1970 where Tony Stark took the Tesseract from the SHIELD facility in New Jersey, and Steve Rogers took four vials of Pym particles.
Finally, there's a timeline where Steve Rogers traveled back to 1948, married Peggy Carter, and lived happily ever after.
So potentially 6 alternate timelines, each with its own Thanos. Do they still exist at the end of the movie? Well, we know the Thanos from timeline #4 is gone, because he got snapped away by Tony Stark. What about the others?
Here's where it gets murky-- the movie (wisely?) allows for multiple interpretations of the Ancient One's explanation to Bruce Banner about the importance of returning the stones, to the point that even the directors and writers of the film disagree about it!
One interpretation says that returning the Infinity Stones prevents the timelines from ever splitting, so timelines 2, 3, 4, and 5 somehow get "absorbed" back into the main one again.
Another says that returning the Infinity Stones to their original timelines is important so that they won't be left without them (for instance, alternate Doctor Strange needs the Time Stone, or he won't be able to defeat alternate Dormammu), but the timelines will still continue to exist and will diverge from the main one because they've all been changed in small or big ways.
If that's the case, then there could be as many as 5 other Thanoses out there. What happens to them? I can see one of two things happening.
-- First, history is changed so that Thanos never becomes so great a threat. Timeline #6, where Steve Rogers lives through seven decades knowing what happened in his own timeline, seems like it could have an outcome like this. If nothing else, ask Captain Marvel to keep an eye on the situation once the 1980s come around. I could see timeline #2 going a lot more smoothly for our heroes too, especially after some Hydra agent reveals sensitive information to Steve Rogers because Hydra thinks he works for them now.
-- The other possibility is that the timeline doesn't experience any significant long-term changes. For instance, you have timeline #1, where the only difference is a missing baseball mitt. Though it seems boring, this is actually the one with the wildest implications. If one of these alternate timelines remains unchanged, that means that its Thanos will collect all six Infinity Stones and will snap away half the life in the universe. Then, five years later, the remaining Avengers will enact the "Time Heist" plan again using the quantum tunnel, and the entire story of Endgame will happen again, ending with Tony Stark snapping away Thanos and the rest of his forces.
This will create the same six timeline branches as the first Endgame, including timeline #1, which will start the loop all over again!
This will never end, meaning that an infinite number of Thanoses will be defeated by an infinite number of Tony Starks!
So we've gone from Thanos winning 14 million times to the Avengers winning an infinite number of times. And I think I need to take a break...
TL;DR: There are an infinite amount of Thanos-es. He is inevitable.
To answer your question.
Using the MCU time travel logic, technically speaking there is an infinite amount of EVERYTHING and EVERYONE in time, but only one of EVERYTHING and EVERYONE at a certain time.
The past is simply an alternate timeline.
So in the past, there are an infinite amount of Thanos-es.
- Since you can travel to any millisecond in the past.
- And during the lifetime of Thanos, he existed on every millisecond.
- So if you travel back to his lifetime a millisecond sooner each time,
you can punch a different Thanos in his
b*llsface every time.
In the future Thanos doesn't exist anymore.
But technically speaking the same principle applies. Although here everyone exists in a Schrödingers cat situation.
Since the future is yet to happen, you don't actually know that someone who is alive now, is dead in the future.
So for the present you this future person is both dead and alive at the same time in the future, until you travel to the future and confirm the persons state.
the canon answer within the MCU is not consistent, because as Paulie-D stated
The directors say yes, the writers say no.
This is because of the mess they created within the MCU.
The problem is that the directors/writers/Marvel got themselves cornered.
The MCU contains both time travel capabilities and the deus ex machina Infinity Stones.
These two concepts mean that technically speaking ANYTHING is possible.
Thanos could come back again, but Marvel obviously doesn't want that (at this moment).
When I say that anything is possible, it also means that the movie could (and logically should) have ended differently.
There are at least 14,000,605 possible outcomes, but here is 1:
- Tony snaps and kills Thanos and his army
- Doctor Strange uses the Time stone to recreate the Quantum tunnel van.
- Captain America travels back to 5 minutes before Thanos-2014 enters 2023
and tells Tony "Don't ask any questions. Come with me!" to bring him back to the current timeline
- Now Thanos is dead, Tony lives (he only missed 30 minutes of his life and the trauma from dying)
and ALL IS FINE
Did you see how easily it can be solved?
And that's exactly why you shouldn't start thinking about the mechanics too much.
Otherwise you will realize that the movie is only written like that because of the way Hollywood works.
Yes and potentially no. As @Paulie_D mentioned the Russos say yes, while the writers say no. The point, as with many of the other holes that have formed due to time travel, is that it is left to the viewer to decide and form their own theories. If you follow the multiverse of Marvel then the various Thanos-es from the comic universes still exist and we can assume a number of others do. They just aren't this Thanos.
If Captain America has to go back to return the stones, it's because they need to fix what they changed in the past. I will call this from now on 'Time Loop'.
Infinity War Thanos knows this rule. He was put back to the time right after he travelled to the future by GAMORA.
Let me explain this. Young Gamora (after Endgame) will acknowledge the problems of the time travel. There are a few time loops:
-Loki, which will be solved in his TV show
-Infinity Stones, fixed by Captain America
-Thanos, Nebula and Gamora
In Guardian of the Galaxy Vol3, Gamora, Thanos and Nebula will understand that they have to go back in time and pretend they don't know anything. Gamora will fall in love with Quill in VOL 3 and pretend she meets him for the very first time in the past. Nebula will have her memory wiped. Thanos doesn't know still where the infinity stones are, but he knows he can't touch the Avengers or he will create another time loop, risking his destiny, so he will just wait.
This explains a lot of things:
Why Gamora tried to kill Thanos and cry in Infinity War - She knows she could create another loop again... And mess this up. However, she tries to stop that before she gets killed for the Soul Stone... But she actually gets caught...
This explains why Thanos knows Tony Stark in Infinity War but not in Endgame! (You are not the only one cursed with knowledge).
That's why Thanos is deeper in Infinity War (like he knows he will fulfil his destiny blah blah blah) and also why he LOVES Gamora because she brought him back to fulfil his destiny!
-And...That's IS the REAL REASON WHY THANOS DIDN'T KILL ANYONE IN INFINITY WAR.
I think, in Guardians VOL3, Gamora will find the current Infinity Stones, let back by Thanos (who knows everything). Though she won't be able to snap them, maybe she convinces Quill to do it or something like that. That's also the reason why James Gunn came back to film this movie... He is the only one capable to explain this mess.
And regarding what people say about the writers and directors. The Russo brothers are not involved in any other movie so I would just listen to the writers instead...