Tom Hiddleston reprises his role as Loki from the film series, while Sophia Di Martino stars as a female version of the character named Sylvie.

Gugu Mbatha-Raw, Wunmi Mosaku, Eugene Cordero, Tara Strong, Jonathan Majors, and Owen Wilson also star in the episode.

At the Time Variance Authority (TVA) headquarters, Judge Ravonna Renslayer receives information sent by He Who Remains via Miss Minutes.

Using a TemPad to avoid Sylvie's attacks, He Who Remains reveals he can anticipate their actions because he has foreseen the past, present, and future and that he guided them to him.

They kiss, but Sylvie uses the TemPad to send Loki back to the TVA headquarters and kills a surrendering He Who Remains, unleashing a multiverse with timelines that cannot be pruned.

[5] Herron and head writer Michael Waldron executive produce alongside Hiddleston and Marvel Studios' Kevin Feige, Louis D'Esposito, Victoria Alonso, and Stephen Broussard.

Herron described her as a "devil on the shoulder" for Loki and Sylvie, and originally had planned for Miss Minutes to fight the pair in the Citadel at the End of Time.

The production break allowed the creatives to reexamine Miss Minutes' role in the episode, resulting in creating a deeper, "protective" relationship between her and He Who Remains than was initially conceived.

[13] Kang was always intended to be a part of the series, since Waldron believed the character fit in a story which involved time travel and the multiverse.

[15] Waldron felt it made "so much sense" to introduce Majors in the series, since Kang is "a time-traveling, multiversal adversary" and thought to be "the next big cross-movie villain".

Waldron believed that the ending they settled on felt "right" and was able to close "one chapter of the story" while providing "thrilling propulsive energy into whatever happens next".

She also felt it was important to show that Loki "still has a fight in his heart" in the scenes in the Time Theater after Sylvie sends him away, even though he has reached his lowest point.

Hiddleston added that Loki's confusion in that moment, processing Sylvie's betrayal after he "made a brave choice", was "unprecedented and it shatters him internally".

Production designer Kasra Farahani took inspiration from the comics for the Citadel at the End of Time, having the Citadel be carved in situ from the asteroid, similar to Petra in Jordan, with it made from "this black stone with gold vein embellishments";[1] the gold was meant to represent "an unknowable kind of technology" since scientific discoveries have shown that asteroids are able to contain "unfathomable cache of precious metals and rare elements".

Leading to his office, Farahani constructed 13-foot-tall sculptures, sentinels of time that each hold half of an hourglass, followed by "an elaborate timekeeping apparatus where the room itself serves as the clock"; these touches were meant to slowly reveal who was in the Citadel without explicitly stating it to the audience.

[21] Herron felt the Citadel set helped Majors' performance of presenting He Who Remains as "the extrovert, but also the introvert of someone that would be living by themselves and only talking to a cartoon clock".

[21] He Who Remains' costume was constructed from elements throughout time, such as a Victorian era cape, shoes from Genghis Khan, and Mongolian pants,[25] with a chest piece meant to evoke Immortus.

[21] For the TVA shown at the ending, Farahani made sure it looked the same as the one featured in all the previous episodes, to help "delay the audience and Loki's understanding that they were in a different place".

This TVA also has a statue of Kang the Conqueror in place of the three Time Keepers, with Farahani working with the visual development team to create the character's look and design.

[34] The episode opens with a sequence that features various archival audio from past MCU projects, including audio of Sam Wilson, Hope van Dyne, T'Challa, Scott Lang, Natasha Romanoff, Peter Quill, Thor, Steve Rogers, Hank Pym, Carol Danvers, Loki, Korg, Classic Loki, Vision, and Sylvie, as well as audio of Alan Watts, Neil Armstrong, Greta Thunberg, Malala Yousafzai, Nelson Mandela, Ellen Johnson Sirleaf, and Maya Angelou;[35] this was an homage to the film Contact (1997).

[41] The opening sequence features "It's Been a Long, Long Time" by Harry James, previously heard in Captain America: The Winter Soldier (2014) and Avengers: Endgame (2019),[42] and the Bollywood song "Swag Saha Nahi Jaye" from Happy Phirr Bhag Jayegi (2018), sung by Sohail Sen and Neha Bhasin.

Over its first five days of release, it also had viewership highs in the United Kingdom (300,000 households), Germany (96,000), and Australia (12,000), which also surpassed the finales for WandaVision and The Falcon and the Winter Soldier.

"[50] Alan Sepinwall at Rolling Stone was "simultaneously thrilled and dismayed" by the appearance of Majors in the episode, noting introducing a series' main villain in the final episode was "bad dramatic structure", and that "it briefly felt as if everything that had been so special and appealing about Loki was being brushed aside in order to hype up a new bad guy for the big screen".

Sepinwall believed if the finale was examined "as setup for more Loki, in addition to letting MCU viewers get accustomed to a version of Kang", "For All Time.

[7] Like Sepinwall, Robinson also felt the Kang reveal should not have worked and noted the large amount of exposition in the episode, stating "There is absolutely zero chance this episode would have worked were it not for Marvel hiring an actor as watchable and unpredictable as Majors", and likened him to Andrew Scott's Jim Moriarty in Sherlock.

She was also glad the finale focused on "character and emotion, and kept the world-ending stakes surprisingly personal" and did not feature a large CGI action set piece in the third act.

Fantastic writing and a standout debut performance combine to create an episode of television that should change a universe (or multiverse) forever."

It's a bold move that makes for a riveting episode and the most unexpected MCU finale yet—even if it's arguably a wildly unsatisfying non-conclusion to the season of TV we just watched."

"[8] David Opie of Digital Spy criticized the introduction of He Who Remains, saying it "came completely out of nowhere" for non-comics readers, feeling that "thematically, another Loki variant would have made for a far more satisfying villain" as that would force Loki "to confront himself and his notions of what it means to be good", opining that characterization was "being overlooked just to move the story along in whatever way Marvel sees fit".