Now, when it comes to which Marvel heroes the MCU can and can't use, it's mostly pretty clear-cut.
The X-Men, The Fantastic Four and Spider-Man are out - as are most of the villains primarily associated with them - and then more-or-less everyone else is in.
The problem is, there are a whole lot of characters who don't fit all that well into that equation. Take the Skrulls, for instance. They' re a galaxy-spanning alien race, who've featured in wide range of Marvel comics, including The Avengers - but, due to their origins in, and frequent adventures involving, The Fantastic Four, they're all Fox's when it comes to the movies.
And so, perhaps it shouldn't be too much of a surprise that...
James Gunn Just Confirmed a Major Marvel Hero Won't Be Appearing in the MCU
Specifically that guy, right there, better known as Gladiator, leader of the Imperial Guard of the Shi'ar Empire, and a pretty-big deal within the Cosmic Marvel Universe.
Asked by a fan as part of a Facebook Q&A, though, Gunn confirmed that, sadly, Marvel doesn't own the rights to the hero:
Which means we won't be seeing him the MCU anytime soon.
Now, seeing as he originally appeared in the pages of the X-Men, that makes a decent amount of sense. However, since it also suggests that the entire Shi'ar empire - a pretty major part of several Marvel storylines (as well as the sworn enemies of the Kree, who've already appeared in Guardians of the Galaxy) - it might just write off a whole lot of future storylines for the MCU, or at least force them to be re-written fairly substantially.
Which...we always kind of suspected, seeing as the Shi'ar haven't been mentioned anywhere in the MCU, but even so...that's actually kind of a big deal.
After all, to all of us Marvel comics fans out there, the idea that the Kree-Shi'ar war isn't ever going to happen in the MCU is actually kind of a downer...