Quicksilver and the Scarlet Witch will appear in Avengers 2, according to Entertainment Weekly.  Director Joss Whedon started a furor last week by letting on that he’d written brother-sister characters into the film, and EW now says it has an independent source confirming it.  It’s still early, though, as Marvel Studios head Kevin Feige pointed out to the magazine, saying "The draft could change six months from now."  

The film is due to be released May 1, 2015 (see "Disney Sets Date for 'The Avengers' Sequel").