Who Are Scarlet Witch and Quicksilver? Everything You Need to Know About the Twins of ‘Avengers 2′

[Editor's Note: Consider yourself warned of spoilers from 'Captain America 2' and 'The Avengers 2.']

After watching the 'Captain America 2' post-credits scenes, one of which introduced Elizabeth Olsen and Aaron Taylor-Johnson as "the twins" (aka Scarlet Witch and Quicksilver), one viewer exclaimed, "Am I supposed to know who they are?" Dedicated Marvel fans across the globe are no doubt rolling their eyes over what, to them, seems obvious, but it still happened.

It's easy to forget how even though Marvel's comic book universe has gone mainstream, thanks to the 'Avengers' movies, there's still a percentage of casual viewers who are only just grasping the surface of the MCU (for newbs, that stands for "Marvel Cinematic Universe") and are blissfully unaware of its implications. While we've provided primers for the uninitiated for such figures as Ultron and the Guardians of the Galaxy, we now turn our attention to the two new superheroes joining 'The Avengers: Age of Ultron.'

A Brief Origin Story From the Comics

While there's a far more detailed history and mythos surrounding Scarlet Witch and Quicksilver, for the purposes of becoming oriented with the film interpretations, here's what you need to know.

Scarlet Witch (aka Wanda Maximoff) and Quicksilver (aka Pietro Maximoff) are the twin children of Magneto (yes, the same Magneto portrayed by Ian McKellen and Michael Fassbender in the 'X-Men' films -- though, to be clear, the 'Avengers' movies are completely separate from 'X-Men'). To briefly graze the surface of their comic book origins, the twins found themselves orphaned shortly after their birth and in the care of a gypsy couple, who were later killed when their home was attacked, an event that would lead the children to their birth father. Not realizing the truth, Magneto enlisted them into his Brotherhood of Evil Mutants terrorist group after saving them from angry townsfolk, who were incited into a riot after seeing Wanda's chaotic abilities get the best of her. Eventually, though, Scarlet Witch and Quicksilver would abandon their evil ways and join up with The Avengers.

Making the Jump From the Comics to the Screen

While Quicksilver's abilities are pretty straightforward -- he has superspeed -- his sister's are a bit more complicated. Marvel describes Wanda's powers as probability altering, allowing her to make the most unlikely things occur (e.g. spontaneous combustion, deflection of objects, etc.), as well as reality warping, through her ability to wield what's referred to in the comics as "Chaos Magic."

For 'Avengers 2,' however, it looks like writer-director Joss Whedon is taking some liberties. Both he and Olsen said that Scarlet Witch's abilities in the film will include minor telekinesis and mind control, and the ability to weave spells -- and by the looks of the leaked set photos, probably some force field action, as well.

Interesting to note is that the inclusion of Scarlet Witch puts a spotlight on the Marvel universe's interpretation of magic and its community, something the past films haven't really highlighted. We'll soon get to see even more magical players when the upcoming solo film for Doctor Strange (aka Stephen Strange, aka Sorcerer Supreme) finally makes the jump to the big screen. (Did you catch the Stephen Strange name drop in the rooftop interrogation scene from 'Captain America: The Winter Soldier'?)

In terms of Quicksilver, Johnson said of his character, "the thing is to think about that he’s an abandoned child. Him and his sister are abandoned and they live in Eastern Europe. There’s more character aspects that I’m interested in than the power aspect."

How 'Avengers 2' Will Deal With the Whole Mutant Problem

Just to reiterate what Disney's Marvel Studios and 20th Century Fox's Marvel division said many times prior, the 'X-Men' and 'Avengers' movies are not connected to each other, though Scarlet Witch and Quicksilver both originated in Marvel comics as mutants and the offspring of Magneto. Because these two characters straddle both universes, it's why we're seeing Quicksilver, for instance, be portrayed in both -- Evan Peters plays him in director Bryan Singer's 'X-Men: Days of Future Past' and Aaron Taylor-Johnson plays him in 'Avengers 2.' However, since Fox owns the film rights to X-Men, Disney cannot reference the twins as mutants, while the former can. With me so far?

Since mutants are inherently part of 'X-Men,' Joss Whedon had to come up with a different sort of origin story, if you will, to describe how Scarlet Witch and Quicksilver got their abilities in 'Avengers 2.'

For those of you who stayed to watch that first mid-credits scene from 'Captain America: The Winter Soldier,' you'll know that actor Thomas Kretschmann made an appearance as upcoming 'Avengers 2' villain and Hydra member Baron von Strucker to introduce "the twins," as he first referenced them. Based on the footage shown, we know that Scarlet Witch and Quicksilver were not born with their powers as in the comics, but were instead the only surviving patients of Strucker's experiments to imbue humans with superpowers -- all the others died in the process.

But where did this serum originate from? Since we also know that, in order to create The Winter Soldier, Hydra injected Bucky Barnes (played by Sebastian Stan) with a similar serum to the one that made Steve Rogers into Captain America, the serum injected into the twins could very well be a variation on that formula and be how Disney addresses that which cannot be named (mutants) in its films moving forward.

So there you have it! Hopefully now casual viewers will understand why the rest of us cannot wait for next year. 'The Avengers 2,' officially titled 'The Avengers: Age of Ultron,' won't hit theaters until May 1, 2015, but perhaps at least the next Marvel movie, 'Guardians of the Galaxy,' will distract us from our impatience.

For more information on Scarlet Witch and Quicksilver, watch our video of Elizabeth Olsen and Aaron Taylor-Johnson from Comic-Con 2014.