Christopher Markus and Stephen McFeely open up about their narrative decision to save the transformation of Professor Hulk for Avengers: Endgame. The last two Avengers movies contained some of the most pivotal character arcs in the Marvel Cinematic Universe. The writers may have prioritized the fates of Captain American and Iron Man in the two-part finale, both of whom could be considered godfathers of the MCU. However, they never lost sight of a creative responsibility that permeated the entire plotting process.
Markus and McFeely have a deep understanding of the MCU and its characters; the writing duo have worked on all of the Captain America movies, Thor: The Dark World, Agent Carter, Avengers: Infinity War, and Avengers: Endgame. This familiarity posed them as the perfect people to helm the fate of multiple characters and bring a conclusion to 24 movies. However, their writing process for Avengers: Endgame wasn’t without its hiccups. One character they spent quite a lot of time deciding what to do with was Bruce Banner/The Incredible Hulk (Mark Ruffalo). Ruffalo’s character spends the majority of Avengers: Infinity War struggling with the Banner/Hulk dynamic after the Hulk loses a fight to Thanos at the beginning of the film.
Speaking to Vanity Fair, Markus and McFeely revealed some changes they made to the Hulk’s individual storyline. In the theatrical version of Avengers: Infinity War, Bruce Banner fights in Wakanda using Tony Stark’s “Hulkbuster” armor because the Hulk is presumably too dejected. One of the original versions of the film did see the Hulk fighting in Wakanda. Markus and McFeely were asked why exactly they decided to rewrite and re-shoot this part of the film. They said the following in response:
McFeely: We had to change it.
Markus: We wanted everybody to have this enormous journey in the five-year-jump [after the Thanos snap], and to really see, in sometimes shocking ways, how the loss had affected them. We hadn't given Banner [a change] because we had transformed him earlier, and he had nowhere to go. And suddenly by needing to take it out of the first movie, it was the perfect thing.
At the beginning of Avengers: Endgame (after losing to Thanos), the Avengers are without hope; Bruce Banner is without the Hulk. After the film’s five-year time jump, it is revealed that Banner found a way to “combine the brains and the brawn." Courtesy of gamma-ray exposure, Bruce Banner and Hulk become Professor Hulk. Seeing an articulate version of the savage character adds another unique element to Avengers: Endgame.
Professor Hulk plays an important role in bringing everyone back from “the snap.” He is the one to don the (Iron) Infinity Gauntlet and snaps all of Thanos' snap victims back. He does this because the Infinity Stones’ radiation is “mostly gamma" — he's sure of himself. This moment is light years away from where we see the character in Avengers: Infinity War. It’s the end of an arc that began with both Bruce Banner and the Hulk insecure with themselves. The creative decision to introduce Professor Hulk in Avengers: Endgame added another satisfying conclusion to a well-told story.
Source: Vanity Fair