There’s still no word on when the Flash may be racing onto the big screen, but we now know that another comic book speedster — Marvel’s Quicksilver — will be appearing in X-Men: Days of Future Past. Evan Peters (American Horror Story) has been cast as the son of Magneto, as reported by CBR.
Joss Whedon recently confirmed that Quicksilver and Scarlet Witch are in the Avengers 2 script (which is in much earlier stages). According to spinoff, the characters are available to both studios (Marvel and Fox), so his appearance in one franchise doesn’t prevent him from appearing in the other.
Update: Marvel and Fox are reportedly in a “legally-negotiated stand-off” over the character at this time. According to HitFix, Fox can’t mention the Avengers in X-Men: DoFP, and Marvel Studios can’t call him a mutant or mention Magneto in Avengers 2.