TRIVIA

Noah Hawley has hinted at the possibility of Charles Xavier appearing in the series. It is currently unknown if Patrick Stewart or James McAvoy would reprise their roles.

Aubrey Plaza's character Lenny Busker was originally written as a middle-aged, drug-addicted man in a mental hospital.

The character of Syd Barrett who is played by Rachel Keller is named after Syd Barrett of the rock band Pink Floyd, whose music was an important influence on the series for Noah Hawley. Barrett left Pink Floyd in 1968 due to mental illness issues.

The second FX series from Noah Hawley. The first series is Fargo (2014).

The character Syd Barrett is frequently shown early in the pilot episode with light reflecting around her head. This is a possible homage to the Pink Floyd tracks "Shine on you crazy diamond" parts 1 and 2 which were about former lead singer Syd Barrett who was also considered mentally ill.

In the pilot, David Selby (Dark Shadows) plays the role of a supervisory researcher studying David.

In an interview with Collider, producer Simon Kinberg compared this series to Breaking Bad (2008).

Jean Smart and Rachel Keller both starred in the second season of FX's Fargo. Jean played Floyd Gerhardt who was the grandmother of Rachel's character Simone Gerhardt. Noah Hawley was so happy with their performances that wrote the roles for them.

The fifth "X-Men" TV series and the first one series in live-action.

SPOILERS

The trivia items below may give away important plot points. In Marvel Comics, Legion (David) causes the alternate universe of a world without Charles Xavier. In this world or the "Age of Apocalypse" Xavier was killed and his legacy of starting the X-Men (et al) was changed. Magneto was the Headmaster of Xavier's School of the Gifted, Apocalypse rules the world, some good guys were evil (and vis versa), only one of the "X-Men" knew the alternate timeline was different/changed.

The title of the show is based on David Haller's codename in the X-Men Comics. David acquired the codename "Legion" due to having hundreds of multiple personalities each with his/her own mutant power. Essentially making him a one man army.

Legion (David Charles Haller) is a character from Marvel Comics. He is the mutant son of Professor Charles Xavier and Gabrielle Haller.

In the montage of David growing up, David sets an expirement on fire while at school and later, a convenience store burns behind David as he walks away. In the comics, pyrokenesis is a power that David commonly uses.

Easter Egg: throughout the series various X's can be found hidden in the background.

All of Lenny's interactions involve David except for one. Syd's first interaction with Lenny is only after switching bodies with David. Although Syd accidentally kills Lenny, no one ever mentions Lenny by her name. Division 3 tells David a girl was killed and Syd tells David I killed your friend. Lenny continues to appear to David even after her death and she shares many personality traits with, Cyndi, one of David's personalities in the X-Men comics. This could very well indicate she may be one of David's personalities.

David suffers from dissociative identity disorder, more commonly known as multiple personality disorder.

In one episode, in a discussion regarding a major location in the series, Audrey Plaza's character says "I mean, what kind of a name is Summerland?". Oddly enough, there is a town called Summerland in British Columbia, roughly 250 miles north of where the series is filmed.