Jane Foster might be the key 'Avengers 4'

At this point the fans are super hyped for the sequel of 'Avengers: Infinity War' that should "fix" the events that happened thatnks to Thanos' Snap.



Thanks to the leaked pics of Avengers 4 we can see that some Time Travel or Alternate realities will be involved in this film, and the avengers will try to get the Infinity Stones traveling to the past before Thanos gets it.

As we saw in Ant-Man and the Wasp, the quantum realm had a big role, and probably will have it again in Avengers 4. It has been widely speculated if the character played by Natalie Portman could return to the MCU. Some Reddit users seem to be convinced that this will be the case, and not only because of the Russo's non-declarations. The central axis of this theory is in a specific scene of 'Thor: The dark world', the second installment of the individual saga of the Norse god played by Chris Hemsworth. This scene can be seen on YouTube.

As we can see, Jane has a brief conversation with the scientists who are carrying out tests on Asgard, and at a certain moment it refers to the 'Quantum Field Generator', which literally allows to "transport molecular energy from one place to another".

This gadget is mentioned again in Ant Man and the Wasp maybe is foreshadwing something that it will be back in Avengers 4 and the Avengers will need backup in this area (because Hank Pym, Janet and Hope Van Dyne are dead).