Spoilers for Infinity War ahead. Now that Avengers: Infinity War is finally here (yay!), there's only one Marvel Cinematic Universe movie to go before fans get the female driven superhero movie they've been waiting for. Captain Marvel is currently slated for release in March 2019, two whole months before Avengers 4, and based on these Captain Marvel theories, it could play a major role in setting up the final fight against Thanos. Marvel has already confirmed that Captain Marvel will have a role in the next Avengers film, and these Captain Marvel theories hint at her role in Avengers 4 in a major way.
The post-credits scene in Infinity War saw Nick Furry send an S.O.S. signal via beeper to Captain Marvel, opening the door to introduce Brie Larson's Captain Marvel to the Avengers team in Avengers 4. Granted, that's assuming Captain Marvel is even alive. At the end of Infinity War, Thanos completed his life's mission, getting all six Infinity Stones and wiping out half the population of every single planet in the universe with a snap of his fingers. Heroes including Falcon and Bucky were vaporized on Earth, while Mantis and Spider-Man disappeared on Titan, proving that no planet was safe from Thanos' mass genocide. Captain Marvel is also at risk of falling victim to Thanos' massacre, but that would make the post-credits scene pretty foolish and unnecessary. So, assuming Captain Marvel is still alive and ready to fight, these Captain Marvel theories might hold the key to her role in Avengers 4.
Captain Marvel Is "The Most Powerful Superhero"
At the world premiere of Avengers: Infinity War, Marvel Studios president Kevin Feige told Variety that Captain Marvel was "the most powerful superhero that we've ever introduced." If there was ever a time the Avengers needed help from the "most powerful" hero, it would be now. Who better to go up against Thanos in Avengers 4?
Captain Marvel's 1990s Origin
Captain Marvel the movie will take place in the '90s, before Captain America was rescued from the ice, which means the Avengers don't yet exist. However, it's obvious that S.H.I.E.L.D. was very active back then under the supervision of Nick Fury and his best agent, Agent Coulson, both of whom are set to appear in the movie. What does this mean for Avengers 4? Well, fans of Agents of S.H.I.E.L.D. know that a big part of the fallout from Captain America: The Winter Soldier was the scramble for top secret weapons and alien artifacts collected by S.H.I.E.L.D. that now had no home or people to protect them from HYDRA and other evil organizations. It's possible that one of these weapons, perhaps one recovered by Captain Marvel in the film, will be just the thing the Avengers need to defeat Thanos and restore the lives taken by the stones in Infinity War.
Another connection between Captain Marvel and Agents of S.H.I.E.L.D. is the Kree, the alien spieces that essentially birthed the Inhumans and was used to save Coulson after The Avengers. Based on the timeline and casting in Captain Marvel, fans already know that the film will dive deep into Kree mythology, specifically through Jude Law's character, Dr. Walter Lawson, who is actually a Kree alien known as Mar-Vell. As detailed by The Wrap, Captain Marvel was just a regular human until she met Mar-Vell, a Kree warrior who mentored her and coincidentally fought against Thanos in what we can assume was a pre-MCU time. It's unclear whether Mar-Vell himself will survive Captain Marvel or return in Avengers 4, but his connection to her and his past with Thanos provide many intriguing possibilities.
The Soul Stone & Vormir
The obscure location of the Soul Stone in Infinity War could play into Captain Marvel. In the Avengers film, it's revealed that the Soul Stone has been hidden on the planet Vormir, a planet which, as pointed out by The Wrap, is in Kree space, aka space that Captain Marvel would be familiar with thanks to her knowledge of the Kree. Furthermore, Feige told Den of Geek that Captain Marvel would be "very much a cosmic film that also has earthbound elements," suggesting that a majority of the film will take place in the cosmos. It's also already been revealed that the plot of the film will revolve around the Kree-Skrull war. Finally, in Infinity War, Gamora clearly states that she has seen a map to the Soul Stone. For there to be a map to the Soul Stone, there would have to be a person who hid it for safekeeping, and for someone to hide the stone on a Kree planet suggests that said person was either Kree or an ally of the Kree.
Given Captain Marvel's cosmic setting and the character's relationship with the Kree, it's possible fans will get to see more of Vormir and the Soul Stone in the upcoming film. Perhaps it was Captain Marvel herself who hid the stone on Vormir as part of the fight against the Skrulls. Or maybe she is the one who inherited the map from the person who hid it there. Assuming it's more than a coincidence that the Soul Stone was kept on a Kree planet, then Captain Marvel herself has to be tied to the Infinity Stone in some way or another.
As fans learn more about Captain Marvel, more theories will undoubtedly arise connecting her to the Avengers 4 and the Infinity Stones, but until then, it definitely looks like, connections to the Soul Stone or no, Captain Marvel is coming to the Avengers, and we can't wait.