With Avengers: Infinity War unleashed, followers of the Marvel Cinematic Universe can't stop discussing their predictions for the sequel. While it won't hit theaters for another year, fans are diving into Avengers: Endgame theories in hopes of figuring out where Marvel will go in Phase Four.
Plenty of questions about Avengers: Endgame exist. How will THAT hero return? Should we worry that Robert Downey Jr.'s contract is finished? Fans desperately want to know, so the rumor mill has been grinding since the first audiences saw the fallout of Thanos's quest for the Infinity Stones.
Before you read any further, consider this your warning: SPOILERS lie ahead. If you're all caught up, then dive in, True Believer, to the most probable and most hopeful fan theories for Avengers: Endgame.
If you waited for Marvel's signature post-credit scene, you know Maria Hill and Nick Fury both fall to Thanos's universal culling. Just before he disappears from existence, though, Fury sends a message out using an odd pager. It falls to the ground, giving viewers a glimpse of a logo - which belongs to the one and only Captain Marvel
If you've followed the MCU release schedule, you know Captain Marvel is slated for March 2019. Her first solo mission is a prequel set sometime in the 1990s. Knowing that, her place in the current MCU remains a bit uncertain. But seeing that logo on the pager told fans a few things: Captain Marvel is alive and well, coming to help, and may be just what the universe needs to undo Thanos's damage.
Of the many fan theories regarding Endgame, most of them deal with a way to fight Thanos and undo his destruction. One theory suggests Thanos will fix things himself, proving his emotions are more central to the plot than the Infinity Gauntlet.
The heroes on Titan nearly remove the Gauntlet from Thanos's hand by exposing him to an emotional and mental attack. Mantis taps directly into his mind, while Peter Quill grills him about what happened to Gamora. But Quill ruins the plan just as the heroes are on the verge of taking the Infinity Gauntlet away, and Thanos ultimately succeeds in eliminating half the life in the universe. And, in theory, this played out exactly as Doctor Strange wanted.
Strange witnessed over 14 million versions of the future and only foresaw one where the heroes win. He then gave up the Time Stone, something he claimed would never occur. Strange's last words to Iron Man before he vanished were that no other way existed. He must have seen the possible outcomes of their actions, and discovered taking the Gauntlet or killing Thanos would end in an even worse fate than what eventually happened.
As a result, Strange orchestrated an attack where Mantis and Quill force Thanos to confront his emotions. Thanos is the only one who can undo what happened, and that moment of emotional vulnerability will ultimately push him to reset the universe in Endgame.
Many aspects of the Soul Stone remain a mystery. Fans never even saw the Soul Stone until Thanos sacrificed Gamora, the only thing he ever truly loved. Thanos wakes with the Infinity Stone in his hand, but we never see how he got it. One fan theory claims the sacrifice didn't reveal the stone, but turned Gamora herself into the Soul Stone.
This could clarify the scene immediately following the snap. Thanos sees a young Gamora in a watery realm. While it may be a dream, the setting is tinged orange - the same color as the Soul Stone.
According to the theory, the half of the universe Thanos kills didn't die, but transported inside the Soul Stone. This theory holds up to scrutiny given what we know about the Soul Stone from the comics. It's the only Infinity Stone that's sentient, and it can trap souls inside itself - placing them in an idyllic world (Adam Warlock suffered this fate for some time in the books). So, nobody actually dies in Infinity War, since they simply moved into the stone - and all the remaining Avengers need to do is free them.
For the MCU, the Quantum Realm is a dangerous dimension where the concepts of space and time become irrelevant. One can only access the Realm through certain means, like using a Sling Ring or shrinking oneself down to subatomic size with Pym Particles. Marvel gave us a glimpse of what this looks like in Ant-Man, and expanded on the Realm in Ant-Man and the Wasp.
One fan theory posits Thanos caused a rift which split the universe in two via a massive quantum event. The universe fans saw at the end of Infinity War remains in the "normal" MCU, while the second universe looks much the same, but is populated with only the people who disappeared at the end of the movie. In that universe, people like T'Challa and Peter Parker instead saw their friends disappear in the same manner they did in the film.
In order to return the divided universe to its original state, a tunnel of sorts needs to be found that can bridge the gap between both pieces and bring them back together. Ant-Man may be the only hero suited to this, as he's one of the only people who's been able to travel to the Quantum Realm and come back in one piece. Ant-Man could team up with Iron Man (maybe employing his B.A.R.F. technology) to marry their tech and come up with a solution that fixes the universe.