We already have frontrunners for casting, but the origin stories for Quicksilver and Scarlet Witch in the upcoming Avengers: Age of Ultron movie are still up in the air when it comes to how they'll fit into an X-men free world.
Since Marvel is legally unable to mention anything about mutants, that means Scarlet Witch and Quicksilver (the children of Magneto) will have to have an origin story devoid of their actual mythology.
So, how can Marvel get away with this?
Here's my theory (let me know what you think and be as harsh as possible. Oh who am I kidding? You will be anyways...)
In the comics, Quicksilver and Scarlet Witch don't actually know they are mutants until later on in their adolescence. They don't even know Magneto is their father. Raised in Europe, the two are just "freaks" with crazy powers and are hunted by people who fear them.
They're saved by Magneto and quickly join his Brotherhood. Eventually, Magneto is taken from Earth by Stranger (JJ ABRAMS?!) and the Brotherhood disbands. Quicksilver and Scarlet Witch then join the Avengers.
My theory is that their origin story will remain intact with the exception of their brief allegiance with Magneto. It might be a little confusing or seem under-explained, but I believe Marvel will be able to pull it off.
That way, if Marvel ever does manage to miraculously acquire the rights to X-men (a pipe dream, but still worth thinking about), they can fit Quick and Witch into the subsequent movies with no problems.
Sound good to you? Let's hope so, because I really want to see these characters hit the big screen, like yesterday.
Jon Negroni is the author of the Pixar Theory and other movie-related conspiracies. For more of his odd opinions you might care about, check out jonnegroni.com or follow him on Twitter @JonNegroni