Just to clarify: These are all theories!
We all love a good villain and Marvel certainly has given us some cool ones over the years. Whether you love them or dislike their portrayal onscreen, they still make the movie more enjoyable. Recently, I read a certain article by Andrew Stowe about how Ronan the Accuser might not be dead. I read his theory and completely agree with him!
He stated that Ronan the Accuser from Guardians of the Galaxy was absorbed into the power gem instead of dying, which is certainly an interesting theory. This is something that isn't uncommon in the comics, as it has happened to several characters, specifically Adam Warlock with the Soul Gem. Like Andrew said in his article, he is too big a character in the comics to be killed off, especially since he has a big role with the Inhumans - who we all know are about to get their own movie.
This got me thinking even more, if Ronan can be absorbed by an Infinity Stone, why not another character we haven't seen since Phase 1? Yes, I'm talking about:
Red Skull! Yes, now that we know the Tesseract is the Space Stone, it would make sense for Red Skull to have been transported into another world or be absorbed by the Stone.
It isn't a crazy theory, if you think about how the Aether from Thor: The Dark World works; it takes it's host and absorbs it's energy. Malekith and the Aether are connected in some way, because when the Aether is awakened, how else can he and all the other Dark Elves wake up at the same time? There has to be some connection. Who knows, we might even see the return of Malekith, but portrayed better.
Abomination (Emil Blonksy):
This got me thinking even more, because we all know that the Winter Soldier (Bucky) will be returning, along with Crossbones in the [Captain America: Civil War](movie:994409) film, but there are a couple more villains that are quite possible to come back. The villain I want to see come back is Emil Blonksy, better known as Abomination.
General Thaddeus "Thunderbolt" Ross:
I believe they have mentioned him twice after the events in the Incredible Hulk. The first in the Marvel One-Shot "The Consultant" and again in an early episode of Agents of S.H.I.E.L.D. during the first season. It would make sense to bring him back for another Hulk film but not without another villain. General Thaddeus "Thunderbolt" Ross.
This guy is a major thorn in Banner's life and if they were to make another movie with him, it should be about his transformation into the Red Hulk. What I think they should do is guest star him in Agents of S.H.I.E.LD. along with General Glenn Talbot. That's just me.
I know I'm blabbering on nothing but theories here, but we all know that they will eventually show him in the MCU, sooner rather than later. That character being? The REAL Mandarin, NOT Trevor Slattery. They've proven that the real Mandarin exists in the MCU, it's only a matter of time before they officially show him.
Again these are just my theories, so nothing is set in stone. Let me know what you guys think!