Here is what we know for sure so far about the MCU’s upcoming Captain Marvel film: Brie Larson will be suiting up as the titular superhero; Samuel L. Jackson has joined the cast in his recurring Nick Fury role; the film will be taking place in 1990, revealed by Marvel President Kevin Feige at Comic-Con; and according to a Feige interview with IGN, the film’s main conflict will involve the Kree-Skrull War.
In order to decipher what this may mean for the plot of Captain Marvel, it will be important to look closely at Captain Marvel’s human identity Carol Danvers, the super-heroin’s connections to this war, and her connections to The Avengers as a whole. Before becoming the superhero (some) know and love, Carol Danvers was a member of NASA intelligence under the authority of Nick Fury. She grew up dreaming of becoming an astronaut and traveling to intergalactic destinations. During her time with NASA, Danvers was assigned the care and study of the original Captain Marvel, — known as Mar-Vell — a humanoid soldier from the alien Kree Empire. Danvers was captured by Mar-Vell’s enemy Yon-Rogg and was exposed to a Kree “Psyche Magneton” during the conflict that changed her mental and genetic makeup, giving her the Kree intelligence and abilities of Mar-Vell. Danvers struggled for some time after this event to control the two sides of her new dual Kree-human personas and suffered blackouts until she began to accept and merge the two sides.
When asked by IGN what the inspiration will be for the Captain Marvel movie, Feige revealed “There’s an entire section of our comics that deal with the Kree-Skrull War and we haven’t tapped into that at and we thought that would be an amazing, huge portion of mythology to belong to Captain Marvel,” continuing, “Captain Marvel will be our twenty-first film in the cinematic universe, and we’ve never seen the Skrulls. How come?” The Kree have already shown up in the universe, appearing in various forms in Guardians of the Galaxy and in the television series Marvel’s Agents of S.H.I.E.L.D.
Captain Marvel has had both history with the Kree and the Skrulls. Both of these humanoid races originated in the Fantastic Four comics and came head to head in the pages of the 1971-72 Avengers comic. The Skrulls are the oldest known interstellar empire within the Marvel universe with the ability to alter their shapes, sizes, and colors — in other words, shapeshift. After traveling to various planets to add new races to their empire, the Skrulls came across the Kree. After learning that the Kree planet was also inhabited by an advanced plant race known as Cotati, the Skrulls developed a test to see which race was superior. The Skrulls named the Cotati the victor. In retaliation, the enraged Kree assassinated both the Skrull and Cotati ambassadors, stole Skrull technology, and began a war that would last for eons.
So to answer Feige’s “how come?”, some speculate the answer could be that Captain Marvel beats the Skrulls so badly in her stand alone film that they simply disappear. The popular opinion, though, and the one supported by Marvel canon, is that the Skrulls use their shapeshifting abilities to hide themselves on Earth in order to make their return at an opportune moment. According to Marvel lore, the Skrulls have a long history of using their abilities to change their appearances in order to implant themselves and conquer other worlds; therefore, it would be no surprise if they plan a similar plot for Earth. During the Skrulls Secret Invasion comic, in fact, it was revealed that the Skrulls had infiltrated both S.H.I.E.L.D. and Earth’s superheroes many years earlier.
And why, might we ask, has Captain Marvel not appeared yet in the ranks of The Avengers? It seems as though Marvel will be answering this question with their particular timeline. By setting the film in 1990, we will not only get a new and nostalgic superhero aesthetic for the franchise (with Carol Danvers being a journalist in her day-to-day, this presents a lot of wonderful pantsuit possibilities), but also takes her out of the present Avengers moment, since we already know that she will not be featured in Avengers: Infinity War, Part I (also revealed at Comic-Con). Carol Danvers has a rocky history with the Avengers, joining their ranks briefly after learning to control her Kree/human dichotomy, but through various circumstances, she joins and leaves the superhero team multiple times thereafter.
Therefore, it is completely plausible to explain away her absence thus far from Avengers films, and an equally valid reason for her to turn up in say Infinity War, Part II or a Phase IV Avengers film. It will also make a lot of narrative sense if the Skrulls reappear in the modern Avengers film canon around the same time as Larson’s Captain Marvel, whenever that may be. With the Avengers already waging a galactic war with Thanos in Phase III, Marvel may put further involvement with the Skrulls off (although fun fact: Thanos’s mother was a Skrull).
Let the speculation continue! Many are now expecting Mar-Vell to definitely show up within Captain Marvel, and if that proves to be true, he will likely be the film’s male lead, assuming they also decide to include Mar-Vell’s human alter ego Dr. Walter Lawson. It all depends on how much of an origin story they want to make it. With most audiences not knowing all too much about Carol Danvers or Captain Marvel, a focused origin story would be a safe bet.