Legion is an American superhero television series created by Noah Hawley for FX, based on the Marvel Comics character of the same name.

Rachel Keller, Aubrey Plaza, Bill Irwin, Jeremie Harris, Amber Midthunder, and Jean Smart also starred, along with Katie Aselton during the first season.

He wanted to show Haller as an "unreliable narrator", including mixing 1960s design with modern-day elements, and filming the series through the title character's distorted view of reality.

All three seasons received critical acclaim for their distinct narrative structure and visual style, as a unique approach to the superhero genre.

After Haller has an encounter with fellow patient Syd Barrett, he is confronted with the possibility that there may be more to him than mental illness where an incident led to the death of his friend Lenore "Lenny" Busker.

In his absence, his Summerland allies have joined forces with Division 3 to stop Farouk's plan to find his real body and amass world-ending power.

David then uses Switch to go back to when he was a child and witnesses various parts of his parents' past including his father Charles Xavier going to war and meeting his mother Gabrielle Haller at a mental facility, his father locating and meeting Farouk, and how Farouk got into him in the first place, though this does bring both sides into conflict with the Time Eaters.

After completing work on the first season of Fargo at FX in 2014, Noah Hawley was presented with the opportunity to develop the first live-action television series based on the X-Men comics, of which he was a fan when growing up.

Hawley was set to write the pilot, and executive produce the series alongside X-Men film producers Lauren Shuler Donner, Bryan Singer, and Kinberg, Marvel Television executives Jeph Loeb and Jim Chory, and Hawley's Fargo collaborator John Cameron.

"[7] Also at that time, Singer explained the executive producers' roles in the series, saying that he, Donner, and Kinberg brought their experience from making the X-Men films, but their involvement generally consisted of giving small notes on scripts and early cuts of episodes.

[63] In early February, Stevens, Aubrey Plaza, and Jean Smart were cast as Haller, his friend Lenny Busker, and therapist Melanie Bird, respectively.

[64][15] Season 3 added relative newcomer Lauren Tsai as Switch, "a young mutant whose secret ability serves as the key to executing David Haller's plan".

[25] It was not feasible to literally translate Bill Sienkiewicz's iconic artwork of the character to the screen, and Hawley wanted the series to have "its own visual aesthetic to it, and part of that is being a story kind of out of time and out of place".

He stated that "the design of a show has to have its own internal logic", and compared this sensibility to the series Hannibal, which he said was "a great example of something that had this almost fetishistic beauty to everything that you saw, whether it was food or violence.

[25][10] Russo felt that "the important part is allowing the humanity of these characters to really shine through", and in addition to an orchestra he used "a bunch of old synthesizers" and "a lot of interesting sound design" to represent the "otherworldly" elements of the series.

After his early meetings with Hawley, Russo developed some initial ideas for the score, and created three different themes to represent Haller.

[83] Landgraf stated, in January 2016, that the series would be set in a universe parallel to the X-Men films where "the US government is in the early days of being aware that something called mutants exist but the public is not".

[84] The next month, Singer said that Legion had actually been designed to fit into the X-Men universe, but also to stand alone, so "you wouldn't have to label" the relationship between the series and the films.

Brandt noted that FX extensively advertised the series, but was debuting the 90 minute (with commercials) premiere at 10:00 pm on a Wednesday night, later than other genre "monster hits" like Game of Thrones and The Walking Dead.

The website's critical consensus reads, "Bold, intelligent, and visually arresting, Legion is a masterfully surreal and brilliantly daring departure from traditional superhero conceits.

"[97] Metacritic, which uses a weighted average, assigned a score of 82 out of 100 based on 40 reviews for the season, indicating what the website considers to be "universal acclaim".

He writes "the sets could be admired independent of the show if they didn't add so much to it, and the entire production raises its artistry to a level atypical of superhero stories (and at least on par with the best design on TV)" and "toss in dynamite performances (Jean Smart, we owe you a rave) matched by sizzling editing most Marvel movies would envy, and boom — 'Legion' is top-tier TV, right off the bat."

He writes "Since Legion's sophomore season started airing in April, I have watched this Bob-Fosse-meets-Maori-tribal-dance scene several dozen times.

and a critical consensus reading, "In its final season, Legion remains a singular piece of visually arresting, mind-bending television that never fails to surprise.

[102] Tim Goodman from The Hollywood Reporter called the third season "weirdly told and wonderfully acted" but also cautioned viewers to not "get hung up on the plot."

His main thoughts on the first half of season 3 are that "Hawley is once again having a blast reimagining a Marvel superhero show and that "he is tripling down on the visual gymnastics and mind-altering aspects.

He writes that "The set design is striking, and Hawley's direction even more so: The pilot is rife with elaborately choreographed shots in which not a detail is out of place.

He felt that the series takes advantage of this change both to show "mind-bending, trippy moments meant to convey to viewers how fractured and disorienting David's perceptions of reality can be" and by having characters like Melanie Bird insist that Haller can improve with treatment and counselling.

Pulliam-Moore explained that other telepaths with mental illnesses in the X-Men franchise—Jason Stryker in X2, Jean Grey in X-Men: The Last Stand, and Charles Xavier in Logan—were all treated with drugs, and praised the alternative therapy explored in the series, as well as the fact that the removal of the Shadow King from Haller's mind was not an excuse to ignore the mental illness issues moving forward.

"[109] Dan Stevens expressed his interest in reprising his role as David Haller / Legion in future Marvel Cinematic Universe projects at CinemaCon in 2024.