In an interview with IGN, Joss Whedon confirmed that the Marvel superheroes Quicksilver and Scarlet Witch will appear in the Avengers sequel. This news comes months after speculation of a possible brother-sister pair being included in the next installment of the franchise.

With the possible exclusion of Robert Downy Jr.’s Iron Man from Avengers 2, rampant rumors have been flooding the blogosphere as to the future direction of the series. Writer-director Joss Whedon has very carefully driven the conversation away from the topics of Downey Jr.’s salary standoff and Iron Man’s status at the end of Iron Man 3. He has instead given the Marvel fanbase new characters to get excited about and speculate as to who will be cast to play them.

Being Quiksilver and Scarlet Witch’s first appearance in film, there has been some backlash from critics regarding the choice to select characters not well-known outside of the comic book world. But like the characters of Thor and Hawkeye who were easily embraced into the mainstream public, Quicksilver and Scarlet Witch have had an extensive history within the Marvel Universe and made multiple appearances in a variety of media.

The two characters were introduced during the Silver Age of Comic Books and created by Stan Lee and Jack Kirby. They debuted in “X-Men” #4 (1964), and the characters’ bios are intricately interlaced with the events of the X-Men timeline. As the twin children of X-Men’s Magneto the siblings could lead to exciting cameos and crossover storylines in future movie projects if Marvel and parent company Disney are able to negotiate with Fox, who currently owns the film rights to the X-Men franchise.

Avengers 2 is slated to start shooting in early 2014 and expected to hit theaters in 2015. Iron Man 3 has gone on to break $1 billion at box office worldwide for a global total of $1.035 billion.