Next year, the tenth anniversary of the MCU, will see Earth's Mightiest Heroes team up with the Guardians of the Galaxy in battle against Thanos. But here's the strange thing: Infinity War seems to lead straight into Avengers 4, due for release a year later. And Marvel is still holding back the title of this next film; Kevin Feige has explicitly stated that it would be a spoiler of some kind. There were brief rumors that the movie's title is actually Avengers: Infinity Gauntlet, but those have been dismissed by James Gunn — and besides, that would be the title everybody's kind of expecting, so it would hardly constitute a spoiler.
So, we can expect a major plot twist of some kind in Infinity War, one so great that Marvel doesn't even want to let us in on the title of Avengers 4 for fear of spoiling it. It's time for a fan-theory...
Thanos's Motivation May Be The Key
Let's start with one of the most intriguing comments to date. The Blu-ray release of Doctor Strange included an exclusive "Phase 3 Sneak Peek," giving us tantalizing hints at the future of the #MCU. As part of the Sneak Peek, #InfinityWar writer Stephen McFeely revealed Thanos's motivation:
"[Thanos'] goal is to rebalance the universe as he sees it. So when he figures out that the Infinity Stones could do this for him in the snap of a finger, that becomes his main goal."
In the comics, Thanos is obsessed with Death, and seeks the unlimited power of the Infinity Gauntlet in an insane attempt to catch Death's eye. In one chilling scene, Thanos used the Infinity Gauntlet to wipe out half the life in the universe. Ironically, Death understood that Thanos was a threat; if all life is extinguished, then nothing else can die, and so Death itself becomes powerless.
It seems that the MCU version of Thanos will be subtly different. I'm sure his idea of "balance" will mean the balance between the dead and the living — keeping the MCU Thanos close enough to the original comic book version — but this is still an intriguing, carefully developed idea.
Balance And The Celestials
In the comics, the idea of "balance" is typically associated with an alien race known as the Celestials. The Celestials serve an entity known as the Fulcrum, and consider themselves responsible for maintaining the equilibrium of all creation. As a result, the Celestials traverse the galaxy, testing inhabited worlds and judging whether or not their races are fit to survive. Should a race fail to meet the Celestials' unknown criteria, then they are destroyed.
The Celestials are becoming an increasingly important part of the MCU. The first Guardians of the Galaxy revealed the severed Celestial head that is Knowhere. Later in the film, the Collector gave us a flashback scene that showed the Power Stone wielded by a Celestial, Exitar, as he pronounced judgment on a world. In the sequel, of course, we met Ego — who believed himself to be the last Celestial. We now know that he was wrong, and that Celestials will play a major role in Thor: Ragnarok, too.
In the MCU, Celestials are beings of phenomenal energy who are powered by a mysterious "living light." They can use this "living light" to manipulate matter at an atomic level; Ego used it to create his own world, but the severed head of Knowhere suggests other Celestials created massive physical forms for themselves. They're powerful, but not invincible, and can be killed when they are cut off from their "living light." The galaxy believes them to be extinct, but it seems the rumors of their demise have been exaggerated.
On the one hand, Thanos's motive in the MCU has been adjusted slightly, giving him a philosophy that seems close to that of the Celestials. On the other, the Celestials are becoming increasingly prominent in the MCU. Is this just a coincidence? Or is Thanos actually working for the Celestials?
The Infinity Connection
Until now, most fans have been assuming #Marvel Studios is drawing inspiration from Jim Starlin's classic Infinity Gauntlet miniseries. Ironically, though, that doesn't seem to be the case; instead, Infinity War seems inspired by the 2013 "Infinity" event, written by Jonathan Hickman. Hickman told a fascinating story, weaving two narratives together in a tremendous miniseries. The first featured Thanos and his Black Order heading to Earth, pursuing Thanos's son. That arc clearly acts as inspiration for Infinity War, which will see the Black Order pillage Earth in pursuit of the #InfinityStones. In fact, some set photos have even suggested comic book-accurate recreations of key scenes from "Infinity."
The second arc featured the Avengers drawn offworld because of a cosmic race known as the Builders, who were seeking to systematically eradicate life across the universe. The Avengers stepped up on to a cosmic stage like never before, with Captain America literally commanding the galaxy's armadas against the Builders. It's possible that, like Infinity War, the as-yet-untitled Avengers 4 will be based on the "Infinity" event. The key difference would be that, in this case, the Avengers are going up against the Celestials, not the Builders.
If this theory is correct, Guardians of the Galaxy Vol. 2 was itself a crucial step along the road to Infinity War — in that it gave us a sense of just how powerful a Celestial can be. #ThorRagnarok will build on that, revealing that the Celestials aren't extinct after all. And Infinity War will see Thanos act as an agent of the Celestials, manipulated by the powerful beings to retrieve the Infinity Stones for them. In Avengers 4, we'll see the heroes take the fight to the Celestials themselves.
Right now, this is just a fan theory; but it's an interesting one, in that it fits rather well with the mysterious pattern of the MCU to date. If Thanos is just a pawn of the Celestials, then Marvel really is about to take the action to the next level. Earth's Mightiest Heroes, and the Guardians of the Galaxy, will be tested as never before — and the MCU really will continue its relentless advance in terms of the cosmic themes that are proving so popular.