Avengers: Infinity War and Avengers: Endgame are American superhero films based on the Marvel Comics superhero team the Avengers, produced by Marvel Studios and distributed by Walt Disney Studios Motion Pictures. They are the sequels to The Avengers (2012) and Avengers: Age of Ultron (2015), and respectively serve as the 19th and 22nd films of the Marvel Cinematic Universe (MCU). Both films were directed by Anthony and Joe Russo from screenplays by the writing team of Christopher Markus and Stephen McFeely. They feature an ensemble cast composed of many previous MCU actors, headlined by Robert Downey Jr., Chris Hemsworth, Mark Ruffalo, Chris Evans, Scarlett Johansson, Don Cheadle, Karen Gillan, Bradley Cooper, Gwyneth Paltrow, and Josh Brolin. In Infinity War, the Avengers, the Guardians of the Galaxy, and their allies unite to prevent Thanos from collecting the six all-powerful Infinity Stones and using them to kill half of all life in the universe. In Endgame, after failing to stop Thanos, the surviving heroes attempt to reverse his actions through time travel.

Preparation for a film adaptation of Jim Starlin's 1991 The Infinity Gauntlet comic book began with Marvel Studios' early films, which introduced the Infinity Stones as plot devices and teased a future storyline with Thanos as the villain. Downey Jr. signed on in June 2013 to reprise his role as Tony Stark / Iron Man, Brolin was cast as Thanos the next May, and many other actors were confirmed to be appearing in the following years. The films were officially announced in October 2014 as Avengers: Infinity War – Part 1 and Part 2. The Russo brothers and Markus and McFeely joined the project in early 2015. The first film's title was shortened to Avengers: Infinity War in July 2016. The second film's title was withheld until December 2018, when it was announced as Avengers: Endgame. The films were renamed because they were intended to tell two different stories. They were designed to conclude the "Infinity Saga" storyline that had been told throughout all MCU films up to that point and end the character arcs of Stark and Steve Rogers / Captain America (Evans).

Both films were shot back-to-back at Pinewood Atlanta Studios in Fayette County, Georgia. Production on Infinity War took place from January 23 to July 14, 2017, with additional filming in Scotland, the Downtown Atlanta area, and New York City. Filming for Endgame took place from August 10 to January 11, 2018, with additional filming in the Downtown and Metro Atlanta areas, the state of New York, Scotland, and England. Final reshoots for Endgame were held in January 2019. The films were the first Hollywood productions to be shot entirely in digital IMAX, using a new camera developed with Arri. Jeffrey Ford and Matthew Schmidt edited both films, and Alan Silvestri returned from The Avengers to compose the musical score. Visual effects companies for both films included Industrial Light & Magic, Framestore, Weta Digital, DNEG, Cinesite, Digital Domain, Rise, Lola VFX, and Perception. Prominent visual effects include the digital characters Thanos and Hulk (Ruffalo) using new performance capture technology, and multiple digital de-aging sequences.

Avengers: Infinity War was released on April 27, 2018, and Avengers: Endgame was released on April 26, 2019, both part of Phase Three of the MCU.

Development Background Throughout their early films in the Marvel Cinematic Universe (MCU), Marvel Studios began preparing for an adaptation of Jim Starlin's 1991 The Infinity Gauntlet comic book by introducing the Infinity Stones as MacGuffins: the Space Stone as the Tesseract in Captain America: The First Avenger (2011); the Mind Stone inside Loki's scepter in The Avengers (2012); the Reality Stone as the Aether in Thor: The Dark World (2013); the Power Stone within the Orb in Guardians of the Galaxy (2014); and the Time Stone within the Eye of Agamotto in Doctor Strange (2016). These MacGuffins and the Infinity Stones are separate objects in Marvel Comics. According to James Gunn, writer and director of the Guardians of the Galaxy films, Marvel decided that the Aether and previous MacGuffins would be used as Infinity Stones during production on The Dark World. Before that decision, the Orb was intended to have red energy in the first Guardians of the Galaxy film. This was changed to purple in post-production to give each of the Infinity Stones its own color, since the Aether was also red. Gunn did not know the importance of the Stones to the wider MCU when he created their backstory, without much thinking, for the Guardians of the Galaxy scene where Taneleer Tivan / The Collector explains the origins of the Stones.

Thanos, a villain who covets the Infinity Stones, was introduced to the MCU in a brief appearance at the end of The Avengers. Many fans subsequently expected Thanos to be the antagonist of the sequel, Avengers: Age of Ultron (2015). However, Joss Whedon, who wrote and directed the first two Avengers films, explained that the character would not be the primary antagonist until a later film because he is "so powerful, he is not someone you can just try to out punch. Like in the comics, you want him to be threading through the universe and to save the big finale for the big finale." Thanos appears at the end of Age of Ultron in another brief appearance, this time shown to have the Infinity Gauntlet, a glove designed to house the Stones. A different Infinity Gauntlet was previously shown in Odin's vault on Asgard in Thor (2011), but following the Age of Ultron scene this first Gauntlet was revealed to be a fake in Thor: Ragnarok (2017). Marvel Studios president Kevin Feige explained that the first Gauntlet was included as a small Easter egg in Thor before an adaptation of The Infinity Gauntlet was in active development, and once Marvel had begun planning that storyline they realized that it would not make sense for the Asgardians to have the Gauntlet. Marvel's internal explanation was that the first Gauntlet was a fake, and Ragnarok was able to address this onscreen. The Age of Ultron Gauntlet is also considered fake, with writers Christopher Markus and Stephen McFeely saying it was a "fashionable practice Gauntlet".

Announcement

In July 2014, Feige said there were "some notions" to where Marvel would want to take a third Avengers film and the studio was aiming for three years between Age of Ultron in 2015 and a sequel. In October 2014, Marvel announced a two-part sequel to Age of Ultron entitled Avengers: Infinity War. Part 1 was scheduled to be released on May 4, 2018, and Part 2 was scheduled for May 3, 2019. Marvel's plan was to film both parts of Infinity War back-to-back. In January 2015, Whedon said it was "very doubtful" that he would be involved with the two films, and rumors spread that the making of Age of Ultron had been difficult for Whedon. Marvel did approach him about writing the next films, and Whedon did not rule out contributing to the screenplays in some way, but he declined to sign on as the main writer and he felt Marvel knew that any contribution from him would not be able to happen soon. Whedon later cited the series' "increasingly enormous" scale as the reason he chose not to return, explaining that he would not be able to give Infinity War "what I would need to".

Anthony and Joe Russo reached a deal by April 2015 to direct both parts of Avengers: Infinity War, after directing Captain America: The Winter Soldier (2014) and Captain America: Civil War (2016) for Marvel. A month later, Markus and McFeely had signed on to also return from the Captain America films, writing the screenplays for both parts of Infinity War. McFeely later recalled that the pair had started negotiating to write the two films without ever actually being asked to do so by Feige or Marvel. Anthony Russo described the two Avengers sequels as the culmination of all the MCU films since Iron Man (2008), bringing an end to some things and beginning others. Marvel called this overall storyline "The Infinity Saga", comprising Phases One, Two, and Three of the MCU. In April 2016, Jon Favreau said he would executive produce the films after doing the same for the previous Avengers films and also directing the first two Iron Man films. Gunn also served as executive producer on the films, working with the Russos, Marvel, and Feige to ensure the Guardians of the Galaxy characters were "well taken care of". In March 2018, Disney moved the first film's United States release to April 27, 2018, so it would be released on the same weekend in the U.S. as in several international markets. That December, the release of the second film was similarly changed to April 26, 2019.

Titles Despite announcing the films as Avengers: Infinity War – Part 1 and Part 2, Feige said they would be "two distinct" projects with shared elements, not one story split across two films. Anthony Russo reiterated this in April 2016, saying the two films were "very very different from one another. It's not a part one and part two scenario, necessarily. They're just two different expressions. I think it creates a misconception that we're shooting them at the same time." The next month, the Russos said the films would be renamed to remove this misconception. In July, Marvel shortened the first film's title to Avengers: Infinity War and left the second untitled.

Anthony Russo said the second title would not be revealed for "quite some time". Feige and the Russo brothers indicated that it was being withheld to avoid giving away plot details. In April 2018, Feige said Marvel chose to withhold the title for so long because they did not want to take the focus away from Infinity War, which happened to Age of Ultron when the next two films were announced before that one was released. Feige felt this approach had backfired due to speculation about the title getting "entirely out of hand" and generating high expectations which the actual title could not live up to. That December, the first trailer for the second film was released and revealed its title to be Avengers: Endgame. The film was previously referred to internally as Avengers: Infinity Gauntlet, which star Zoe Saldaña accidentally revealed in 2017.

Writing Process