Director Nick Fury, the team is a United States–based organization composed primarily of superpowered and gifted individuals, described as "Earth's Mightiest Heroes", who are committed to the world's protection from a variety of threats.

Arranged as an ensemble of core MCU characters originally consisting of Tony Stark / Iron Man, Steve Rogers / Captain America, Thor Odinson, Bruce Banner / Hulk, Natasha Romanoff / Black Widow, and Clint Barton / Hawkeye, it later expands to include 16 total members.

Once Feige became studio chief in 2007 and formed his creative team, his strategy involved creating individual films for each major character in Phase One, beginning with Iron Man (2008) and concluding with The Avengers (2012).

[6] In 2012, the Asgardian Loki teleports to the Joint Dark Energy Mission Facility on Earth, where he steals the Tesseract and brainwashes Clint Barton and Dr. Erik Selvig using his scepter.

[9] Eventually, the World Security Council launches a nuclear missile towards Manhattan, but Stark intercepts and flies it through the wormhole, destroying the Chitauri mother ship and stopping the invasion.

In the aftermath, Stark and Barton retire, Banner disappears, and Thor decides to find the Infinity Stones, while Rhodes, Sam Wilson, Wanda, and the Vision join the team.

The divided Avengers meet and fight at the Leipzig/Halle Airport; Rogers, Wilson, Barton, Maximoff, Barnes and Lang clash with Stark, Rhodes, Romanoff, Vision, T'Challa and new recruit Peter Parker.

[27] Wilson, Barnes, Maximoff, Strange, Parker, T'Challa, Groot, Quill, Drax, and Mantis are blipped, leaving Stark and Nebula stranded on Titan while Thanos escapes.

Rogers becomes a grief counselor, Stark lives with his wife Pepper Potts and daughter Morgan, Thor becomes an overweight alcoholic afflicted with depression, while Banner integrates his intelligence within the Hulk's body.

[58] In an alternate 1988, Howard Stark and Peggy Carter form a response team composed of Hank Pym, Bill Foster, T'Chaka, Wendy Lawson, and Bucky Barnes to subdue a young Peter Quill under Ego's influence.

[59][60] In an alternate universe on Christmas Eve, Stark and Rogers dress up as Santa Claus and an elf respectively at a shopping mall, while Barton and Banner try to maintain crowds at an Avengers toy action store.

Later, a tear opens up, with Carter saving Loki but not Queen Hela, resulting in her being hunted down by Sir Harold "Happy" Hogan and the Royal Yellowjackets under the new King Thor's orders.

Carter takes the Scepter and uses the Time Stone inside Stark's device, exposing a time-displaced Rogers, who inadvertently created the temporal anomaly during a battle with Thanos.

The surviving heroes—consisting of Sam Wilson, Monica Rambeau, Bucky Barnes, Marc Spector, Alexei Shostakov, Melina Vostokoff, Shang-Chi and Nakia—eventually repel the monsters for the next ten years.

[52] Many characters have been affiliated with the Avengers in the Marvel Cinematic Universe: Samuel L. Jackson makes his debut in a cameo appearance as Nick Fury, director of S.H.I.E.L.D., in a post-credits scene in Iron Man.

[77] Jackson confirmed that he had been in discussions to reprise the role of Fury from Iron Man's post-credits scene in the film's sequel, but that contract disputes were making a deal difficult.

[83] Favreau chose Downey, a fan of the comic,[84] because he felt the actor's past made him an appropriate choice for the part, explaining "The best and worst moments of Robert's life have been in the public eye.

[86] Marvel entered into early talks with Emily Blunt to play Natasha Romanoff / Black Widow,[87] though she was unable to take the role due to a previous commitment to star in Gulliver's Travels (2010).

[103] In response, Norton's agent Brian Swardstrom decried Feige's statement, calling it "purposefully misleading" and an "inappropriate attempt to paint our client in a negative light".

[118] In July 2009, Penn talked about the crossover process, desiring to "kind of shuttle between the different movies" while emulating the structure of comic books to ensure the films were connected.

[122] In March, it was reported that Penn had completed the first draft of the script, and that Marvel editor-in-chief Joe Quesada and Avengers comic-book writer Brian Michael Bendis had received copies.

Marvel quickly began working to hire Whedon to write and direct, only mandating that Loki be the antagonist, a battle featuring the Avengers and villains take place, and the film to be completed prior to its May 2012 release.

[142] Whedon enjoyed the storytelling opportunities from introducing a character with telepathic powers, explaining "it meant we could spend a little time inside the Avengers' heads—either their past or their impressions of what's going on, or their fears, or all of the above".

[159] Feige revealed that Captain Marvel, who headlined her own MCU film in 2019, appeared in an early draft of the screenplay, but was removed since the character was not yet cast, saying, "We didn't want to introduce her fully formed flying in a costume before you knew who she was or how she came to be".

[187] Executives at Marvel Entertainment balked at the idea of Captain America and Iron Man coming to blows at the end of the film and wanted the Avengers to unite to fight Zemo and the super-soldiers at the Hydra base in Siberia instead.

[210] After the announcement of Infinity War and Endgame, many established MCU actors were confirmed to be joining Downey and Brolin, including Hemsworth, Ruffalo, Evans, Johansson, Cheadle, Bettany, Olsen, and Anthony Mackie as Sam Wilson / Falcon.

[214] Actors who returned for Endgame include: Downey, Hemsworth, Ruffalo, Evans, Johansson,[215] Cumberbatch,[216] Cheadle,[217] Holland,[218] Boseman,[219] Olsen,[220] Mackie,[221] Stan,[222] Gillan,[215] Cooper,[223] and Brolin.

[263][264] In November 2012, 20th Century Fox announced plans to create their own shared universe, consisting of Marvel properties that it holds the rights to including the Fantastic Four and X-Men, with the hiring of Mark Millar as supervising producer.

[265] X-Men: Days of Future Past (2014) was Fox's first step towards expanding their stable of Marvel properties and creating this universe,[266] ahead of the release of a Fantastic Four reboot film the next year.

[267] In November 2013, Sony Pictures Entertainment Co-chairman Amy Pascal announced that the studio intended to expand their universe created within Marc Webb's The Amazing Spider-Man series, with spin-off adventures for supporting characters, in an attempt to replicate Marvel and Disney's model.