Planet Hulk Arc
Everyone knows that "The Hulk" and "Thor" are the two heavyweights in Avengers uniform. Their mere presence can easily shift the battle in their favor, which is probably why they were not included in the "Captain America: Civil War" plot.

To satisfy the craving of fans, Marvel Cinematic Universe (MCU) decided to feature both powerhouse in the upcoming "Thor: Ragnarok," which hints of massive comic book plot. The storyline has been a hot subject of speculation for months now, but there are already some hints on how everything will play out.

"[Thor] ends up on a gladiatorial planet where his head is shaved and he’s forced to fight for his life," MCU insider explained. "Thor knows that he has to get to [some object] to defeat Hela and Loki and he has to get off the planet."

And this is apparently where The Hulk comes in ...

"[He] runs through all of his alien opponents in gladiatorial combat, even without his trademark hammer. Finally, Thor has to face the current champion of the arena, and wouldn't you know who that ends up being? The Hulk."

Of course, comic book fans will know exactly what this means – 'Planet Hulk' is next.

Published in Incredible Hulk #92 back in 2006, the 'Planet Hulk' storyline saw the Hulk banished to an alien world after the secret group of heroes known as the Illuminati decides that he's just too dangerous to remain on Earth.

After landing on the planet Sakaar, the Hulk is taken into slavery – forced to fight in gladiatorial combat. And after besting hero after hero in the arena, it's not long before The Hulk seizes his chance – killing the Red King to become the new leader of Sakaar.

Illuminati is formed by "Iron Man" at some time in the aftermath of the Kree-Skrull War, and probably after the Avengers/Defenders war. Iron Man realizes that each of the individual members had information about these alien races beforehand, and they could have collectively stopped it.

Illuminati is composed of the following:
  1. "Namor," ruler of the oceans and represents the antihero mindset.
  2. Tony Stark aka "Iron Man" represents the Avenger type of hero, one who understands and appreciates that a hero can work with the government, rather than outside of it. He also represents the common man, as he possesses no natural superhuman abilities.
  3. Reed Richards represents the science-based part of the superhero community.
  4. "Black Bolt" represents the Inhumans, who are an important part of Marvel history and play an important part in events that have not yet come to pass. He also represents a ruler/king archetype, one that has also been filled by Namor.
  5. "Doctor Stephen Strange" speaks for the mystical/non-scientific side of the Marvel universe.
  6. "Professor Charles Xavier" of the X-Men is there on behalf of the mutant community.
The only individual who was ask to join the group, but outright refuses to meet or even participate with the others is the "Black Panther," who fears the association will end in less than altruistic actions.