Elizabeth Olsen and Aaron Taylor-Johnson play Scarlet Witch and Quiksilver respectively. These two new Avengers form part of the greater story in the sequel, Avengers: Age of Ultron (2015). To what extent is still greatly unknown but as far as us fans are concerned, they will be an awesome addition to the already big numbers of heroes involved in the movie!
There are going to be a number of cool battles in the film, with one of them taking place in a forested area, which may or may not lead to a confrontation with Baron Von Strucker and their first encounter with "The Twins" aka Quicksilver and The Scarlet Witch. This sequence is said to be near the opening of the film and will be where we see our first "hero shot" of the team together.