Captain America 5 has the chance to bring back more MCU villains such as Justin Hammer, or it could adapt more villains from comics, like Sin.

Iron Man's choice to die in James' place and take out Red Skull makes for an interesting ... Tony creates a specialized armored suit powered by an arc reactor, which keeps him alive.

Over the years, Doctor Doom has sparred not only the Fantastic Four, but also Spider-Man, Red Skull ... 2008's 'Iron Man', leaving him disfigured and retreating inside a powerful suit of armour ...