Marvel Studios and writer-director Joss Whedon recently revealed that Earth's Mightiest Heroes will be adding two new faces in 2015's "The Avengers 2," namely the mutant twin siblings Scarlet Witch and Quicksilver

Although there's been no news about casting, we've put together a list of possible candidates. However, because they've never appeared on the big screen before, there are a few things to consider when trying to guess who Marvel may select to play Wanda and Pietro Maximoff

1. Chemistry is key. As superpowered siblings, Scarlet Witch and Quicksilver are extremely close to one another and have a powerful bond. Marvel will likely cast one of them first, and then find a partner who can form a believable rapport with the first on cast, as opposed to casting two independent choices. 

2. Their background. The comic book version of the characters have Eastern European backgrounds, so it's likely that Marvel will lean in that direct (or, at least, Europe in general) when choosing actors, and -- with Russia's growing importance at the global box office -- it could work in their favor to cast performers with ties to that region. 

3. The age game. Likewise, the characters were originally introduced in the 1960s "X-Men" series in their early adult years, although both were later aged in the comics. With further franchises in mind, Marvel will likely cast young, but could go either way. 

4. They've got daddy issues. Last but not least, Quicksilver and Scarlet Witch's father is none other than "X-Men" villain Magneto. As Marvel doesn't own the screen rights to the character, they'll likely just have to ignore this facet of the duo's background. Will that give Whedon and Marvel further license to change Quicksilver and Scarlet Witch's characters even more?


With all that in mind, HitFix's Gregory Ellwood offers his casting ideas for Quicksilver and the Scarlet Witch in Joss Whedon's "The Avengers 2." 

Which of these actors and actresses would you like to see join "The Avengers 2"?