Mutant Twins Mania! Quicksilver and Scarlet Witch Confirmed For ‘Marvel’s The Avengers 2′:

"Twentieth Century Fox (or, rather, now 21st Century Fox) may own the screen
rights to Magneto, the leader of the Brotherhood of Evil Mutants. But they
apparently don't own the screen rights to his kids.

Marvel fans will be happy to know that at least two new characters have been
confirmed to appear in "Marvel's The Avengers 2": Quicksilver and Scarlet Witch.
Joss Whedon hinted at last week's Hollywood premiere of "Iron Man 3" that he
had written a "brother-sister act" into the script for the "Avengers" sequel, which
immediately had fans speculating that he meant the popular mutant duo.

Marvel Studios head honcho Kevin Feige is putting on a poker face about the
whole thing, though he emphasizes that nothing's set in stone until the final draft
has been set in stone."

See:

http://movies.yahoo.com/blogs/movie-...174633462.html