Largely ignored by the MCU, MCU's Thanos, not Ultron, would be the saga’s big bad, but the second Avengers film could have still set the narrative for the rest of the Infinity Saga.
While Ultron had been a part of Marvel Comics for decades, the 2013 miniseries Age of Ultron by Brian Michael Bendis put the villain back on the radar, proving that Ultron could work as an antagonist for the entire Marvel universe. The Age of Ultron movie does not share many similarities with the Age of Ultron comic arc other than the name, mostly because the MCU was still very small in of the number of characters and what properties it could use. Still, Ultron had the potential to be a landmark for the Marvel Cinematic Universe – even if the plan was for Thanos to be MCU Phase 3’s final villain.
Avengers: Age of Ultron had enough setups to set the narrative for Phase 3, even though Ultron was designed to be a one-off villain only. There were many storylines involving each of the Avengers that could have been paid off throughout Phase 3, but most of those were either retconned or simply skipped. Age of Ultron was a moderate success compared to Infinity War and Endgame would have played out differently – but the entirety of Phase 3 leading up to those two films would have changed as well.
Thor’s Quest For The Infinity Stones Leads Somewhere
Age of Ultron ends with Thor saying that he is going on a quest for the Infinity Stones – a power that was starting to make a fuss not only on Earth but in the rest of the universe. Thor had a side-arc in Age of Ultron after having his mind played with by Wanda, followed by the infamous exposition-heavy pool scene in which Thor was “briefed” on the dangers of the Infinity Stones. However, when the MCU later revisits Thor in Phase 3 with quest for the Infinity Stones – with no actual insight on how that quest went on. Essentially, the MCU quickly retconned that Thor was supposed to look for the Infinity Stones.
Had Age of Ultron’s Thor setup been paid off, then Thor: Ragnarok would have been a quite different story. Hela and the prospect of Ragnarok happening could have still been in the movie, but at least the first act of Thor 3 would have followed the God of Thunder looking for the Infinity Stones. Thor knew for sure where three Infinity Stones – Mind, Power, and Reality – meaning there were other three for him to find. Thor’s quest could have led him to Xandar and made his encounter with the Guardians of the Galaxy happen way before Infinity War.
Hulk’s Time In Sakaar Is Actually Shown
Of all the Age of Ultron setups for Phase 3, Hulk’s time off-world was perhaps the one to be best paid off. Still, compared to the significance of Hulk disappearing at the end of Age of Ultron, his encounter with Thor right at the beginning of Phase 3 was a bit anticlimactic. If Marvel really wanted to follow up Hulk’s story in Age of Ultron, then the best route would have been to make a Planet Hulk film rather than combining that storyline with Thor: Ragnarok.
Hulk’s main story in Age of Ultron is that he was essentially a danger for the team and for the entire planet, even though the Hulk had learned to fight alongside the Avengers. The Age of Ultron ending could have led to a Planet Hulk film in which audiences would follow the struggle between She-Hulk: Attorney at Law, and there are even rumors of a World War Hulk film, but that storyline could have been completed far earlier had Marvel doubled down on the Age of Ultron setup
Bruce & Natasha’s Relationship Extends Through Infinity War
By far the most criticized decision made in Age of Ultron, the relationship between Bruce Banner and Natasha Romanoff was quickly wrapped up at the beginning of Avengers: Age of Ultron with a brief exchange of looks between the two characters. How that relationship was written in Age of Ultron was extremely problematic. Had Marvel decided to move forward with it, Avengers: Endgame
Vision Is Given A Bigger Role In The Infinity Saga
While Vision is only born towards the end of the Age of Ultron, the character received a lot of attention in the film. Vision had been set up through the first two acts of Age of Ultron, and his awakening is what essentially saves the world from Ultron. Vision was perhaps the most powerful Avenger during the events of Age of Ultron, as Wanda was just now starting to use her powers and Thor had yet to unlock his full power potential. Age of Ultron also made sure to point out that Vision was worthy of lifting the Mjolnir. However, Vision’s appearances in Phase 3 not only drastically reduced his power but also downplayed his importance to the story.
Had Age of Ultron set the narrative for Phase 3, then Vison would have continued to be among the most powerful and central Avengers. As such, Vision would have received a bigger role in Vision’s fate in Infinity War would most likely still be the same, but his role in the Infinity Saga would not be restricted to being a MacGuffin.
Thanos Attacks The Avengers Directly
Age of Ultron’s post-credits scene sees Thanos grab his gauntlet while saying, “Fine, I’ll do it myself.” While the doesn’t make very clear how exactly Thanos was watching the Avengers’ battle with Ultron unfold, it strongly suggests that the Mad Titan was waiting for Earth’s Mightiest Heroes to be destroyed due to their own mistakes. With Ultron failing in destroying the Avengers, Thanos would then go to Earth himself to eliminate his stronger adversaries before collecting the Infinity Stones that existed on that planet. That storyline was completely abandoned in Infinity War, and by the time Thanos finally arrived on Earth, there was only one stone left for him to collect.
Avengers: Age of Ultron's Thanos setup would have led to a much different structured Infinity War. Thanos would go to Earth first instead of looking for the other stones across the galaxy. There would have been a more direct confrontation between Thanos and the Avengers on Earth, with the Avengers perhaps not splitting into small teams as it happened in Infinity War. Still, the outcome of the Avengers’ battle with Thanos would still be similar to that of Infinity War’s Battle of Wakanda, as Thanos had to win first so that the stakes for Avengers: Endgame could be high.
