'Avengers: Endgame': 8 Theories on How the Heroes Will Undo Thanos' Snap

Ant-Man, the Mirror Dimension and more speculation over how the Avengers will come out on top.

The guessing game is almost over.

In a matter of days, Avengers: Endgame will arrive in theaters with answers to dozens of pressing MCU questions, most importantly: How will the gang manage to bring half of the universe back to life?

In the year since Infinity War was released, countless theories have sprung up regarding how the remaining Avengers will undo Thanos' infamous snap, which turned cherished characters like Black Panther, Star-Lord and Spider-Man to dust. Considering this is the Marvel Cinematic Universe, things like time travel and alternate dimensions aren't so far-fetched, which means there are many ways the team could pull off a one in 14,000,605 chance of victory.

Let's break down eight of the most popular theories about Endgame:

1. The Avengers Let Thanos Win

After handing over the Time Stone to Thanos (Josh Brolin) in Infinity War, Doctor Strange (Benedict Cumberbatch) seemingly hinted that it was actually part of a bigger plan, informing the others: "We're in the endgame now." Considering that oh-so-ominous word is in the title of the forthcoming film, speculation that Thanos' victory is an inevitable step in ultimately defeating him has only heightened.

How can allowing Thanos to kill off half the universe ensure the Avengers' success? A safe bet is that reversing time is a factor, but what needs to transpire before the Mad Titan is vulnerable? In the sole clip released from the film, the team reveals that Thanos has used the stones a second time. Were they waiting for this?

2. It's Ant-Man to the Rescue

A common-held theory is that Ant-Man (Paul Rudd) plays a pivotal role in the return of "the fallen." His storyline has been closely tied to the Quantum Realm, where space and time don't work at all like we're used to. (He was there when Thanos snapped his fingers, which may have saved him from obliteration.) The trailer shows the remaining super team clad in new white suits, which fans theorize are designed for traveling through the Quantum Realm based on how closely they resemble Ant-Man suits used in the past.

All of which is to say, betting that Ant-Man will be key in defeating Thanos is understandable.

Although unlikely, there's, uh, another Ant-Man theory involving the superhero shrinking down and flying straight up Thanos' keister, before returning to normal size, thus destroying his enemy from the inside out! Producer Trinh Tran's reaction to this particular theory isn't promising, though. "The most interesting one was the Thanos and Ant-Man one," she told ET with a laugh. "That was...entertaining to read, for sure."

3. Resetting the Timeline

Some theorize that much of the world-building that's taken place will be undone via time travel in order for the Avengers to succeed. This means that the dead heroes would ultimately be brought back, but that some -- or all -- of the events in the 21 films leading up to Endgame would be undone. Conveniently, this could allow Marvel to eventually recast Thor, Iron Man and Captain America, originally played by Chris Hemsworth, Robert Downey Jr. and Chris Evans (the latter of whom has confirmed he's done after this film).

Considering the significance placed on Endgame and the sea change that's rumored to be in the works for the MCU, this reset option feels plausible.

4. The Mirror Dimension

The Mirror Dimension was first presented in Doctor Strange, a spell which, when cast, looks and feels like reality, but the consequences are contained within this alternate world, protecting everyone else. Though Strange was among those dusted in Infinity War, these international posters borrow the glass-shard imagery we saw when the Mirror Dimension was summoned in the past.

According to this theory, either Strange somehow cast the protective spell before Thanos' snap or someone else -- perhaps Wong (played by Benedict Wong) -- might employ the tactic to contain the effects of the Snappening. We already saw many of our heroes turned to dust, so the Mirror Dimension clearly wasn't involved. But could it be if the Avengers go back in time?

5. Call in the Valkyrie

The Asgardian warrior (played by Tessa Thompson) was completely absent in Infinity War, but recently appeared on her own character poster for the sequel as one of the survivors of the snap. It's anyone's guess where she's been in the interim, but unless the filmmakers are misleading fans about her inclusion here, Valkyrie will play a significant role in Endgame. We saw her kick some serious butt in Thor: Ragnarok, though mostly as a scrapper. What is she capable of when she fully embraces her Valkyrie side?

6. Loki Lives (...Or Will Live)

Just as the release of the Spider-Man: Far From Home trailer spoiled that Peter Parker would return to the land of the living, fans know that we'll be seeing Loki again. Disney already announced a live-action show centered on the God of Mischief for its upcoming streaming platform, Disney+, with Tom Hiddleston teasing on Instagram, "Loki. More stories to tell. More mischief to make. More to come."

Sure, there are rumors that the show is a prequel exploring Loki's past, but if the Avengers are bringing back the likes of Winter Soldier and Scarlet Witch -- who also have Disney+ series in the works -- who's to say Loki can't be brought back as well? If so, he might prove helpful in bringing down Thanos, considering their past dealings.

7. The Real Threat Is in the Quantum Realm

Although Thanos appears in the trailers, he is not featured as prominently as he was leading up to Infinity War. Considering that film centered on the uber-villain, it's possible the follow-up will focus on other challenges for the Avengers. (Similarly, the big bad was relegated to the background of Endgame posters, with the original Avengers front and center.)

Could this mean that the film will be largely devoted to, say, navigating the Quantum Realm? During visits to the infinitesimally tiny world in Ant-Man and the Wasp, Hank Pym (Michael Douglas) and Janet van Dyne (Michelle Pfeiffer) encountered monstrous tardigrades, which she later revealed would eat you. And those aren't the only creatures inhabiting this place. It's possible the Quantum Realm will be where the Avengers face their biggest obstacles.

8. There's a 7th Infinity Stone

Although Thanos has filled his gauntlet with six Infinity Stones, his collection may not be complete. There is a seventh stone, the Ego Gem, hidden within a realm known as the Ultraverse -- at least in the comic books. The Ego Gem holds the essence of an omnipotent creature known as Nemesis.

In Infinity War, Wong explained the origin of the six stones, but never mentioned the Ego Gem. Either he hasn't learned of its existence yet, or the gem has been omitted from the MCU (for now).

One thing is certain: Endgame will require a massive game-changer for the Avengers -- perhaps even bigger than Captain Marvel (Brie Larson) -- in order to undo Thanos' dusting. As for what form that game-changer comes in, we'll find out when Avengers: Endgame opens in theaters on Friday.