They were designed to conclude the "Infinity Saga" storyline that had been told throughout all MCU films up to that point, including ending the character arcs of Stark and Evans's Steve Rogers / Captain America.

[44] For the last four months of the year, the pair spent most of their time in a conference room with executive producer Trinh Tran—the representative from the "Marvel Studios Parliament" for the Avengers films—as well as Feige and the Russo brothers whenever they were free.

[51] The Russos did make some decisions that Gunn felt were disconnected from how he wrote the Guardians in his films, and he particularly dismissed Star-Lord's vengeful rage towards Thanos at the end of Infinity War upon realizing Gamora's fate as a choice he would not have made.

[69] Regarding the ending of Infinity War with Thanos wiping out half the universe, Markus stated that stopping before he snapped his fingers or without all of the Stones would have been like hitting a pause button, and the pair wanted to create a more definitive break between the two films.

The Russo brothers suggested putting the scene at the start of Endgame, and the writers felt this was a good move because it reinforces the feelings that the audience had at the end of Infinity War before continuing the story.

"[49][82] The groupings included: Tony Stark / Iron Man, Dr. Stephen Strange, Peter Quill / Star-Lord, Peter Parker / Spider-Man, and initially Bruce Banner / Hulk, and Wong;[49][83] Thor and the Guardians of the Galaxy, with Thor, Rocket, and Groot ultimately splitting off on their own; Wanda Maximoff and Vision; Thanos and Gamora; and Steve Rogers / Captain America, Natasha Romanoff / Black Widow, Sam Wilson / Falcon, Bucky Barnes / Winter Soldier, Banner, and T'Challa / Black Panther.

The writers did not dwell on the romance between Romanoff and Banner, as established in Age of Ultron, beyond including a "loaded look between the two" because they considering it unrealistic as they would be more focused with Thanos; Maximoff and Vision's relationship was implied to have further developed since the events of Civil War.

[86] The Russos also revealed that, despite not appearing in Infinity War, the events of the film killed Betty Ross and Sif, previously portrayed in the MCU by Liv Tyler and Jaimie Alexander, respectively.

Whedon enjoyed the approach the writers and Russos took in Infinity War, giving Thanos "an actual perspective and [making] him feel righteous to himself", since the Death storyline was "not a concept that will necessarily translate".

[110] After the announcement of Infinity War and Endgame, many established MCU actors were confirmed to be joining Downey and Brolin, including previous members of the Avengers Chris Hemsworth as Thor, Mark Ruffalo as Bruce Banner / Hulk, Chris Evans as Steve Rogers / Captain America, Scarlett Johansson as Natasha Romanoff / Black Widow, Don Cheadle as James "Rhodey" Rhodes / War Machine, Paul Bettany as Vision, Elizabeth Olsen as Wanda Maximoff, and Anthony Mackie as Sam Wilson / Falcon.

[114] Additional actors reprising their roles in Infinity War from the various MCU franchises include Benedict Cumberbatch as Stephen Strange from Doctor Strange, with Benedict Wong as Wong;[115] Tom Holland as Peter Parker / Spider-Man from Spider-Man: Homecoming (2017), with Jacob Batalon as Ned,[116] Isabella Amara as Sally,[117] Tiffany Espensen as Cindy,[118] and Ethan Dizon as Tiny;[119] and Chadwick Boseman as T'Challa / Black Panther from Black Panther,[111] with Danai Gurira as Okoye, Letitia Wright as Shuri,[111] Winston Duke as M'Baku, and Florence Kasumba as Ayo.

[120] Sebastian Stan also appears as Bucky Barnes / Winter Soldier from the Captain America films,[121] along with Tom Hiddleston as Loki and Idris Elba as Heimdall from the Thor and Avengers films;[111][122] Iron Man supporting actress Gwyneth Paltrow as Pepper Potts;[123] Benicio del Toro as Taneleer Tivan / The Collector from Guardians of the Galaxy;[124] William Hurt as Thaddeus Ross, who first appeared in The Incredible Hulk (2008);[125] and Kerry Condon as the voice of Iron Man's A.I.

[127] Jon Favreau was to reprise his role as Harold "Happy" Hogan, while co-director Joe Russo had a cameo appearance as a paparazzi photographer, but this scene did not make the theatrical cut of the film.

Known collectively in the comics as the Black Order,[132][133] the actors playing the characters were soon revealed to be Tom Vaughan-Lawlor as Ebony Maw,[134][135] Terry Notary as Cull Obsidian, Carrie Coon as Proxima Midnight,[136] and Michael James Shaw as Corvus Glaive.

[148] Sanada had originally been offered to play Zero in John Wick: Chapter 3 – Parabellum (2019), but an Achilles tendon injury forced him to leave the role for Mark Dacascos, so he saw his casting as Akihiko as a "consolation prize".

[153] Actors who returned for Endgame include: Downey, Hemsworth, Ruffalo, Evans, Johansson,[154] Cumberbatch,[155] Cheadle,[156] Holland,[157] Boseman,[158] Olsen,[159] Mackie,[160] Stan,[161] Hiddleston,[162] Wong,[163] Klementieff,[164] Gillan,[154] Bautista,[165] Saldana,[43] Cooper,[166] Paltrow,[167] Brolin,[168] Pratt,[159] and Wright.

He ultimately agreed to return at the insistence of his son, who reminded him how good he had felt on the sets of The Winter Soldier and Civil War in addition to assuring him that Endgame would be the "biggest movie" in the world.

(2013–2020), had been approached by Marvel Studios regarding his availability for Endgame, with visual effects company Cantina Creative eventually using a photo of Whitehall in imagery for the film's time heist information screens, which was ultimately cut.

The imagery would have also featured the likenesses of previous MCU actors such as Erich Redman as Schneider, Anatole Taubman as Roeder, Toby Jones as Arnim Zola, Thomas Kretschmann as Baron Wolfgang von Strucker and Claudia Kim as Helen Cho.

[188] Yvette Nicole Brown and Ken Jeong, who played Shirley Bennett and Ben Chang respectively in Community, appeared in Endgame as a Camp Lehigh agent and a security guard.

[194] Production designer Charles Wood previously worked on The Dark World, Guardians of the Galaxy, Age of Ultron, and Doctor Strange,[195] but found the increase in scale with Infinity War and Endgame to be a particular challenge.

[202][203] The time-travel suits in Endgame were designed by Marvel's head of visual development Ryan Meinerding to combine elements of the technology related to Ant-Man, Iron Man, and the Guardians of the Galaxy.

[205] Perception also worked on the closing credits for Endgame, opting to create "something that felt personal [and] sentimental", that would also remind the viewer of "the last ten years" of the MCU and was "a love letter to the fans".

[147] For Infinity War's final scene, the filmmakers partnered with Indochina Productions, a studio based in Thailand, to acquire footage of the Banaue Rice Terraces at Ifugao, Philippines.

[254] Opaloch says that the lighting in the scene with Stark sending his goodbye message to Potts "shows you where he is emotionally and physically" with the cyan coloring coming through the ship's window representing deep space and the starscape.

[268] Due to the amount of filming that was required for these reshoots, the production split into four units, with the Russo brothers taking one each and the other two being supervised by visual effects supervisor Dan Deleeuw and Ford, respectively.

Port noted there was "a wide spectrum of designs in terms of what he would look like", with some options including having Hugo Weaving reprise the role with make-up, had he returned, and a version "where the Tesseract did very bad things to his appearance, so he was much more skeletal".

The company also worked on the small fight between Stark, Parker, Strange and the Guardians on the ship, which required full character animation, blaster and web effects, CGI daggers, Quill's mask, Mantis's antennae, and damage to the Q-Ship.

Schulz noted that part of the sequence's difficulty was because "at a later point in the process the decision was made to not move forward with the filmed plate of Nick Fury—instead we would do a camera takeover and switch to a full CG shot.

[298] There were also talks of digitally inserting Cassie Lang into the funeral sequence as a guest, because she was not included in the original filmed version, but the filmmakers decided against it because the attendants were honoring Tony Stark's sacrifice and her inclusion was not necessary.