Marvel Studios has teased that the Scarlet Witch and Quicksilver had abilities prior to Hydra's experiments in Sokovia. One theory suggests Mister Sinister may have experimented on Sokovian citizens decades before Hydra arrived in the nation. Mister Sinister could explain the Scarlet Witch and Quicksilver's mysterious abilities, and connect the superpowered twins to the X-Men.

The introduction of one iconic villain in Marvel Studios' upcoming X-Men reboot could answer major questions concerning the origins of the Scarlet Witch and Quicksilver in the MCU. Elizabeth Olsen and Aaron Taylor-Johnson debuted as Wanda and Pietro Maximoff, respectively, in the mid-credits scene of 2014's Captain America: The Winter Soldier, but made their full debuts in 2015's Avengers: Age of Ultron. While Pietro Maximoff's Quicksilver unfortunately met his demise in Age of Ultron, Wanda Maximoff has had a transformative career in the MCU, leading to her embracing her identity of the Scarlet Witch...