Quicksilver Scarlet Witch
Quicksilver and Scarlet Witch in Avengers 2Marvel

Marvel fans are looking forward to watching new superheroes Quicksilver and Scarlet Witch in the upcoming Avengers: Age of Ultron. While there is a lot of mystery surrounding the super-powered siblings, Marvel's recently released digital comic Avengers: Age of Ultron Prelude - This Sceptre'd Isle Infinite Comic #1, had revealed their origins.

Remember this post-credits scene from Captain America 2: The Winter Soldier?

This was the first time fans got a good look at Quicksilver and Scarlet Witch. Both these characters are all set to take forward the Marvel Cinematic Universe. The new 'Infinite Comic' — Marvel's term for its digital-first releases — reveals what happened to Loki's sceptre after the battle of New York in the first Avengers movie, and the role it plays in the activation of the powers of both Quicksilver and the Scarlet Witch, states The Hollywood Reporter.

According to ComicBookMovie, Avengers: Age of Ultron Prelude reveals how the sceptre went from being in the possession of The Avengers to Baron Von Strucker in Captain America: The Winter Soldier.

The story also links to the current plotline of Marvel's Agents of Shield where, just like the character Skye, Pietro (Quicksilver) and Wanda (Scarlet Witch) are seemingly Inhumans as "Strucker, acting on behalf of Hydra, used the sceptre on test subjects in the fictional European city of Sokovia to 'unlock' any powers they might have."

The comic also reveals that they're willing test subjects and not captured by Hydra — which raises the question as to why they're shown in captivity in the post-credits scene.

Avengers: Age of Ultron will release in theatres on 1 May, 2015.