The Marvel Cinematic Universe as fans know it will come to an end with Avengers: Infinity War. Now, it's time to look forward to its sequel.

The Russos' Avengers 4 releases next May - based on a script by Captain America and Infinity War scribes Christopher Markus and Stephen McFeely - and brings an end the 22-movie narrative that began a decade ago. That not only means defeating Thanos but also saying goodbye to the core MCU superheroes, such as Iron Man, Captain America, and more. Although not much is known about the movie, there are quite a few ways in which the story can play out based on what has been revealed thus far.

Thanos Defeats Himself

Josh Brolin Thanos Avengers Infinity War

Thanos does that to finally satisfy Mistress Death - the one person/being he's longed for his entire life - whereas in the movies, he does that to balance the universe so that every life form could thrive without worrying about consuming too many natural resources. No matter how Thanos goes about it, it's clear from his battles and his past that he doesn't truly deserve to harness the power of the Infinity Stones - and that will be his undoing.

Thanos is already a worthy opponent on his own, but with the Infinity Stones, he's impossible to beat. There's nothing in the universe that can stop someone who wields a completed Infinity Gauntlet... unless that person allows themselves to be defeated. That's exactly what Thanos has done in the comics over the years, and it's something that Adam Warlock points out in Infinity Gauntlet, which is why Warlock waited for the moment in which Thanos let himself be defeated - either by self-imposed sensory deprivation or something else. So, Thanos may allow himself to be vulnerable the second time around in Avengers 4, which will give the Avengers, and whichever remaining heroes are left in the universe, a 0.5 percent chance at success.

The Avengers Trade Their Souls

Avengers Infinity War Ending - Iron Man

The Red Skull had been tasked with guiding Soul Stone seekers for decades. To get the Soul Stone, Thanos had to sacrifice the thing he loved most: Gamora. A soul for a soul.

Although there are six Infinity Stones, the Soul Stone is peculiarly different from the rest. It holds a special place amongst the pack and it requires a sacrifice to obtain it. So, it only seems fitting that perhaps the remaining team - most of which are played by actors and actresses whose Marvel contracts are up - will trade their lives to Infinity War lineup is also perfectly balanced.

Page 2 of 2: Nebula's Comic Ending, Gamora Defeats Thanos, & Iron Man's Sacrifice

Nebula Thanos MCU

Nebula's Infinity Gauntlet Ending Comes True

Comic book fans know that Avengers: Infinity War didn't follow the source material literatim, at least not with regard to how certain events unfolded on the big screen compared to the comics. Still, that doesn't mean that some comic book moments can't be recreated or used in Avengers 4. After all, Nebula defeating Thanos and saving the universe.

In order to rid himself of any and all vulnerabilities, Thanos had left his body behind and entered the astral plane. But the one thing he didn't think of was physically protecting the Infinity Gauntlet, which was still on his left hand. So, Nebula seized the opportunity and stole the Infinity Gauntlet before anyone could stop her. Then, she used the Gauntlet to revert everything back to the way it was 24 hours before. While a bit more happens after everything returns to "normal," the movie version could stop there. Considering that Black Panther.

Gamora Defeats Thanos

Gamora and Thanos in Avengers 4

Adam Warlock knows Thanos the best in the comics, and that's part of the reason he Adam Warlock won't the MCU for quite some time. Thanos not only loves Gamora but the film also shows that Gamora knows him the best, which means she could be the key to saving the universe in Avengers 4.

Avengers: Infinity War revealed Soul World towards the end of the film, in which a young Gamora and the rest of Thanos' victims, as a result of the snap, are trapped in. It's a byproduct of being "killed" by the Soul Stone, which is why it required a sacrifice to obtain. She could escape Soul World (as Silver Surfer, Adam Warlock, and others had done in the comics) and bring an imbalance. Then, she could assume Nebula's comic book arc by stealing the Infinity Gauntlet from Thanos and restoring the universe back to the way it was. If there's anyone that could perform such a feat now, it's Gamora. Plus, that would bring her story (and Thanos' story) full circle.

Tony Stark Sacrifices Himself To Save The Universe

Avengers Infinity War - Doctor Strange and Iron Man

Robert Downey Jr.'s Tony Stark has been at the heart of the Marvel Cinematic Universe ever Iron Man released in 2008. So, one of the most somber ways to bring the MCU's first saga to a close would be for Iron Man to sacrifice himself to save the universe... and defeat Thanos. Throughout his life and even as a superhero, Tony was considered a selfish person who wouldn't sacrifice himself to save others. Instead, he'd find another way to save everyone. But that may change in Avengers 4 when it comes to facing off against the Mad Titan with the Infinity Stones on the line.

There are many ways in which Tony could sacrifice himself, just like he tried doing with the nuclear missile in Doctor Strange's plan requires Tony staying alive (for now), which is why he gave the Time Stone to Thanos, despite explicitly saying that he wouldn't do so no matter what the circumstance. Of course, we'll just have to wait and see what happens.

More: Avengers 4: Every Update You Need To Know