The Red Skull was "killed" when he finally got his hands on the Tesseract (better known to comic book fans as the Cosmic Cube) at the end of Captain America: The First Avenger. However, you never really saw him die. Instead, it appeared as if he may have been transported elsewhere, something which makes a return seem like a definite possibility. Assuming the Red Skull was indeed taken to another realm, there's every chance that, like Captain America, he was frozen in time. A great way of explaining his return could be when all those portals were opened in Thor: The Dark World, or possibly even some sort of development with the Terreract in the upcoming Avengers: Infinity War. The only thing which makes this unlikely as of right now is Hugo Weaving's comments that he doesn't want to reprise the role. It would be a great shame to lose the actor, but it actually wouldn't be in the least big difficult to recast a villain who looks like this. Either way, it's essential that the Red Skull return - his story with Cap feels far from over. Which other MCU characters could return? Share your preferred resurrections down in the comments.