3. Alexander Skarsgard - Sentry
Though the MCU Master Plan that we mapped out only had a small side-role for the hugely powerful guardian of the universe, he remains a hugely intriguing character, and one who could be easily written into future Avengers or Guardians Of The Galaxy movies considering the central premise that he wiped his existence out of collective memory in fear that his dark side - The Void - would lead to death and destruction. The idea of a watchman overseeing Earth and the rest of the universe is a good one, and would be a particularly good way to bridge the gap between the Avengers and the Guardians Of The Galaxy, while the arcs that see Sentry turn rogue are some of his more engaging and would offer a significant threat to even the likes of Hulk and Thor. Alexander Skarsgard would be an easy choice for the character - he has the otherworldliness required, based on his performance in True Blood, and his Swedish physique would suit the traditional design of the character.