Originally Played By: Emma Fuhrmann
Replaced By: Kathryn Newton
How It Went Down: While Fuhrmann initially took implicit the relation of Scott Lang/Ant-Man's girl from Abby Ryder Fortson (who appeared successful Ant-Man and Ant-Man and the Wasp) aft the MCU staged a five-year time-jump successful Avengers: Endgame (turning Cassie into a teen), the workplace announced successful 2020 that Newton would beryllium playing Cassie successful Ant-Man and the Wasp: Quantumania. 

While Cassie's appearance successful Endgame was constricted to conscionable 1 scene, she becomes 1 of the main figures successful the threequel, which is apt the crushed down the recasting.

"To us, aft the events of Infinity War and Endgame, it truly occurred to america that Cassie's going to beryllium 18 successful this movie! That's great!" manager Peyton Reed told Nerdbunker. "The full taxable is time, and however overmuch clip he's missed, and his main information is just, 'I privation clip with my daughter.' I emotion the thought of Scott inactive relating to Cassie arsenic a kid, but she's not. She's a young big now, she has her ain ideas astir what it means to bash bully successful the world, and she's trying to find her dependable arsenic a hero, and she tin besides beryllium a small captious of her father."

Originally Played By: Edward Norton
Replaced By: Mark Ruffalo
How It Went Down: Has determination ever been a much tumultuous relation than that of Bruce Banner/the Hulk?

Initially, Eric Bana played the mean greenish instrumentality successful 2003's Hulk, which is not considered to beryllium portion of the MCU canon. When that movie flopped some critically and astatine the container office, Marvel decided to reboot, with Norton taking implicit successful 2008's The Incredible Hulk.

The movie made $265 cardinal but Norton and the MCU didn't look to marque for a potent pairing, with reports of originative differences resulting successful his exit.

"We person made the determination to not bring Ed Norton backmost to represent the rubric relation of Bruce Banner successful the Avengers," Marvel said successful a connection up of accumulation opening connected The Avengers. "Our determination is decidedly not 1 based connected monetary factors, but alternatively rooted successful the request for an histrion who embodies the creativity and collaborative tone of our different talented formed members. The Avengers demands players who thrive moving arsenic portion of an ensemble."

Shots officially fired, with Norton's campy calling the connection "offensive" and "mean-spirited," and going connected to contradict the allegations, calling it a "financial decision" connected Marvel's part.

Fortunately, Marvel yet recovered the close acceptable successful Ruffalo—and realized the quality worked amended successful ensemble settings, not standalone movies. "Mark Ruffalo's Hulk portrayal acceptable a batch of things close successful a mode that made america each precise happy," Marvel president Kevin Feige said astatine a property conference.

"[Hulk is] my generation's Hamlet. Everyone's gonna get a ace astatine it earlier it's each said and done," Ruffalo erstwhile joked to Vanity Fair.

Originally Played By: Damion Poitier
Replaced By: Josh Brolin
How It Went Down: When the Mad Titan made his film debut successful the mid-credits country of 2012's The Avengers, he was played by the stuntman. But erstwhile Thanos afloat stepped into his relation arsenic the MCU's large atrocious in Guardians of the Galaxy, Brolin was the histrion formed to marque the iconic snap. 

"We wanted idiosyncratic to beryllium much than conscionable the voice," Feige explained successful a 2014 interrogation with Collider. "Josh did the show arsenic well. We were looking astatine a privation database of, 'Wouldn't it beryllium large if' names, and his sanction was connected it. And you look astatine his look and the performances helium gives, helium could beryllium Thanos without immoderate effects. He has that benignant of look and that benignant of gravitas to it."

Poitier would aboriginal marque a little quality arsenic a mercenary successful 2016's Captain America: Civil War.

Originally Played By: Terrence Howard
Replaced By: Don Cheadle
How It Went Down: The Empire prima originated the relation of Tony Stark's champion person successful 2008's Iron Man, but helium was subsequently replaced by Cheadle implicit a declaration dispute, which Howard infamously spoke retired astir during a 2013 quality on Watch What Happens Live.

"This is going to get maine successful a batch of trouble, but it turns retired that the idiosyncratic I helped go Iron Man, erstwhile it was clip to re-up for the 2nd one, took the wealth that was expected to spell to maine and pushed maine out," helium said, referring to Robert Downey Jr. "We did a three-picture deal, truthful that means that you did the woody up of time. It was going to beryllium a definite magnitude for the archetypal one, a definite magnitude for the second, a definite magnitude for the third. They came to maine with the 2nd and said, 'Look, we volition wage you one-eighth of what we contractually had for you due to the fact that we deliberation the 2nd 1 volition beryllium palmy with oregon without you. And I called my person that I helped get the archetypal job, and helium didn't telephone maine backmost for 3 months."

Asked wherever helium stood with Downey (who has ne'er publically responded to Howard's comment) aft the deal, Howard replied, "Oh, I emotion him. God's going to bless him." The erstwhile co-stars reunited months aboriginal astatine producer Brian Grazer's wedding and snapped a selfie. "Nice to spot my aged person again," Howard wrote connected Instagram, adding that "life's excessively short."

Originally Played By: Hugo Weaving
Replaced By: Ross Marquand
How It Went Down: While the Lord of the Rings star "loved" playing the villain in Captain America: The First Avenger, his sentiment of Marvel soured aft a declaration quality regarding his imaginable instrumentality successful 2012's The Avengers. 

"They'd pushed backmost connected the contracts that we agreed connected and truthful the wealth they offered maine was overmuch little than I got for the precise archetypal one, and this was for 2 films," Weaving explained to Time Out successful 2020. "And the committedness erstwhile we archetypal signed the contracts was that the wealth would turn each time. They said: 'It's conscionable a dependable job, it's not a large deal.' I really recovered negotiating with them done my cause impossible. And I didn't truly wanna bash it that much. But I would person done it."

Ultimately, Marquand played Red Skull erstwhile the quality returned arsenic the Stonekeeper in Avengers: Infinity War and Endgame, and The Walking Dead alum besides lent his dependable to Ultron Sentries successful 2022's Doctor Strange successful the Multiverse of Madness.

Originally Played By: William Hurt
Replaced By: Harrison Ford
How It Went Down: The Star Wars and Indiana Jones fable is acceptable to articulation the MCU as the president of the United States in the upcoming Captain America: New World Order pursuing Hurt's decease astatine the property of 71 successful March 2022.

The precocious Oscar victor originated the relation successful 2008's The Incredible Hulk, going connected to look successful 4 much movies, making his last quality successful Black Widow.