Marvel Studios President of Production Kevin Feige is the man behind the curtain of the entire film franchise. Joss Whedon is helping oversee Phase Two to ensure it builds towards The Avengers 2, but it’s Feige who’s in charge of the master plan of the entire Marvel Cinematic Universe. He knew Guardians of the Galaxy was going to happen a long time before The Avengers hit the big screen, and even before last summer’s record-breaking team-up film, Feige went on record talking about characters for its sequel.

We always knew the core team of Captain America, Hulk, Iron Man and Thor would return for The Avengers 2, but the more interesting question is what new characters will join them. Joss Whedon may have just let slip who the newcomers may be.

Seven months before The Avengers hit theaters, Kevin Feige said the following about new characters in the next big team-up:

“Absolutely. That’s the fun of it — introducing new characters. Seeing: ‘How will things change after Iron Man goes through his next adventure? After Thor goes through his next adventure? If we do another Cap adventure, how will things change? The dynamic between them? Their own worlds? So that the dynamic in Avengers 2 is actually quite different than it is in the first one.”

Almost a  year later, after The Avengers completed its run in theaters, Marvel co-chairman Louis D’Esposito got a little more specific:

“We’re currently working on Phase 2 and we have ‘Iron Man 3,’ ‘Thor: The Dark World’ and ‘Captain America: The Winter Soldier,’ so we returned to those franchises to enlarge them, but I think in ‘The Avengers 2′ will see one or two new characters.”

Immediate speculation goes to the obvious choices of Wasp – who was originally in the script of The Avengers 1 – and Ant-Man, who’s now getting his origin story told later that year after The Avengers 2 hit theaters. Doctor Strange is also confirmed for a Phase Three solo film introduction (no release date yet) so counting him and Ant-Man out, Wasp is the only safe bet when it comes to new characters. There’s of course chat of Phase Two characters helping support the main team, with Falcon and War Machine potentially joining the roster like Black Widow and Hawkeye did the first time around. Who else?

Cue the world premiere of Iron Man 3 in Los Angeles last night where Yahoo! Movies chatted with Joss Whedon. Whedon says that he’s not only locked in the story, but the first draft of the script is done. In talking about how he’s going to “top” The Avengers and the other Phase Two films, he revealed something very interesting.

“I try to think of this as its own movie. Sometimes, ya, I feel pressure, how do you not? And by the way, Shane [Black] not helping! Iron Man 3 not helping! Because I saw this and said, ‘Aw, man, he really got it right!’ The pressure continues! But you put that aside, when you’re in the story, when you’re dealing with these characters that you love, that everybody loves, when you got the new characters sliding in next to them, it’s very exciting. Then I don’t feel pressure. Then it’s like I’m reading my favorite comic.”

But which characters? Later in the interview in talking about script drafts, he revealed:

“I’ve done enough shows and movies to be comfortable with that. You do come to a point where we all agree. ‘Okay. Oh, I’ve got these two characters, two of my favorite characters from the comic book; a brother-sister act. They’re in the movie. That’s exciting.’ You know, you lock certain things in”

The only brother-sister act from “the comic book” that makes sense for The Avengers 2 would be Quicksilver and Scarlet Witch, two classic members of The Avengers team who are also in the Ultimate version of The Avengers for which the films draw much of its inspiration for story arcs and and costume/character designs. But wait, they’re mutant characters so only Twentieth Century Fox – the studio holding the X-Men rights – can use them, right? Not so. Kevin Feige:

“It’s a little complicated, but if they [Fox, which holds the X-Men rights] want to use them in the X-Men movie they could, [but] if we want to use them in The Avengers movie, we could.”

By legal technicality, since the pair are both mutants and early members of The Avengers, both studios could in theory, use the characters. The bigger issue are the story and character arc implications of including the pair because the Marvel Cinematic Universe – as created by Marvel Studios – doesn’t include mutants (yet) and as fans know, Quicksilver and Scarlet Witch are children of Magneto.

Will they rewrite their origins, family ties and sources of superpowers for The Avengers 2? Is Whedon even referring to them in The Avengers 2. Has Mark Millar (Fox’s comic book movie consultant) and Fox worked with Marvel to – like Millar publicly spoke about – make sure the film universes don’t contradict each other?

Throw in Hugh Jackman’s Wolverine by some fanboy miracle and we get:

[Click to Enlarge]

Quicksilver’s real name is Pietro Maximoff and his mutant power gives him superhuman speed. Think of him as Marvel’s Flash. Scarlet Witch’s real name is Wanda Maximoff and her abilities are a little more complex. She can essentially change reality by altering probabilities and at times, she’s completely changed the Marvel universe, even de-powering most of mutantkind.

Another possibility is that the brother-sister act could be taken figuratively, and that Whedon could simply be referring to a type of partnership involving a new character. Remember Tony Stark’s reference to Agent Coulson dating a “cellist” in The Avengers? Whedon had a very specific reason for including that line and it could be referring to Kate Bishop, the other Hawkeye who happens to play the cello. Her and Clint Barton (played by Jeremy Renner) act as siblings in the books, but having two archers in The Avengers 2 is a stretch.

Whedon will undoubtedly be asked to clarify the next time media catches hold of him, but for now, let the speculation begin!

Iron Man 3 releases May 3, 2013, Thor: The Dark World on November 8, 2013, Captain America: The Winter Soldier on April 4, 2014, Guardians of the Galaxy on August 1, 2014The Avengers 2 on May 1, 2015, Ant-Man on November 6, 2015, and Doctor Strange sometime after that.

Let me know on Twitter @rob_keyes what Avengers you want to see in the sequel!

Sources: ColliderYahoo! Movies