Quicksilver (Marvel Cinematic Universe)

Pietro Maximoff, known also under the alias Quicksilver, is a character in the Marvel Cinematic Universe set to appear in Avengers: Age of Ultron and is the twin brother of Scarlet Witch. He will be portrayed by Aaron Taylor-Johnson. Quicksilver was created by Stan Lee and Jack Kirby.

Early Life
Pietro Maximoff was born in the country of Sokovia alongside his twin sister Wanda. They became orphans when a mortar shell hit their house. Years later, Sokovia became a warzone. Pietro and Wanda participated in different riots in a attempt drive the foreign forces out of their country. However, all these riots were planned by HYDRA, who had taken up residence in Sokovia and used the riots as cover in their illegal experiments. One day, List, a HYDRA scientist approached them to offer the opportunity to get enough power to drive war out of Sokovia. His sister Wanda was skeptical but he did not. Pietro was determined to free Sokovia and convinced his sister to accept. As results of these experiments, Pietro achieved superhuman speed; while Wanda won numerous mental powers as telekinesis, hypnosis, and energy projection.

Captain America: The Winter Soldier
Quicksilver and Scarlet Witch appear in a mid-credits scene with Baron Strucker, which confirmed that they were not present at SHIELD's headquarters at the time HYDRA was defeated there and Operation Insight was shut down due to Baron Strucker's actions. Strucker also revealed he intended to use them for an unspecified purpose.

Avengers: Age of Ultron
Quicksilver initally follows Ultron because he believes Tony Stark to be evil. When he realizes that Tony is a hero, and that Ultron plans to exterminate humanity, Quicksilver turns on Ultron and helps the Avengers save the people of Sokovia from Ultron. However, he is shot and killed by Ultron in the process.