Quicksilver and the Scarlet Witch are two of only a handful of characters both Marvel Studios and Fox (the holders of the X-Men movie rights) are able to use in their movies. The former are at a serious disadvantage though - they aren't allowed to mention that the duo are mutants or that their father is Magneto, so, as a result, expect big changes. One change could come about as a result of 'The Twins' in Avengers: Age of Ultron being Inhumans. It was initially thought that Baron von Strucker would use Loki's staff (an Infinity Gem) to simply give them powers, but a prequel comic revealed just days ago that he actually used that to "unlock" the abilities already within the brother and sister. When you consider that the exact same thing has been happening with characters on Agents of S.H.I.E.L.D., this makes perfect sense and adds credibility to those Inhuman rumours. Throw in the fact that Marvel has recently revealed that Magneto isn't their father in the comic books, and all signs currently point to Quicksilver and Scarlet Witch being Inhumans.
