We don't really know too much about the Captain Marvel movie, other than that Brie Larson will star and Niki Caro and Elizabeth Wood will direct. Sure, the original plans were to have Carol Danvers cameo at the end of Avengers: Age of Ultron, but those plans fell through. According to Joss Whedon, Captain Marvel is too important a character to be introduced this way (a simple cameo).
Talking about Doctor Strange, Kevin Feige also revealed a new detail about Carol Danvers’ first outing in the MCU. The Marvel boss said that 2019 will bring the origin story of the character. Does this mean that she'll miss the Infinity War? It is most likely, although we wouldn't bet on it.
Call me Captain Marvel. pic.twitter.com/IgqRIb9ijM
"” Brie Larson (@brielarson) July 24, 2016
Here is what Feige said, via CBM:
Benedict is an amazing actor and totally different than Hemsworth and totally different from Downey. And we want to stay true to who he was in the books. The metamorphosis of what he goes through is more drastic than Tony (Stark), and that was fun to chart. I guess Panther isn't really an origin story since we saw him already in Civil War, but his standalone certainly introduces you to 99% of his world which you never saw before. And Captain Marvel is certainly an origin story from the start.
In the comics, Carol Danvers gains her superpowers after being caught in an explosion with the original Captain Marvel. The original hero was of Kree origin, a race that was already introduced in the MCU (Ronan the Accuser was a Kree fanatic).
So there is this possibility for Danvers to appear in the Infinity War, if the Kree alien race will also be featured. Given the scale of the War (and the fact that Thanos may have a grudge against the Kree), we may see this character before 2019.
Mar-Vell (Comic Vine)
