The Legion TV series is just under a month away from premiering on FX. It focuses on David Haller (Dan Stevens), the son of Professor Xavier, as he grew up bouncing from mental facility to mental facility. Although he is the son of Charles Xavier, he will not be featured in the series.
In an interview with IGN, the show's producer Lauren Shuler Donner indicated why this was done and the approach they were taking with David's character.
“We just don't want to get into the Xavier world, because that's not what this show is about. Probably the driving mystery is, yes, who is David? But not in that sense. It's more, "Is David schizophrenic? Is he crazy? Or does he have powers?" That is the mystery. "Who is David?”
David Haller is one of the most powerful mutants ever, and this Legion series will essentially be breaking down his character from the opposite perspective. The comics featured David Haller learning what his abilities were essentially through practice. The TV series will work backward and begin in the mental facilities where David begins to realize that he isn't sick or schizophrenic, but rather a mutant with abilities.
Even if the show mentions Xavier a bit later down the line, it will not be the Stewart or McAvoy versions as Legion is set within its own universe. Donner indicated that "Yes, we're in a different world. Exactly" Donner also indicated that they do have an overall vision for the side characters of X-Men to have a larger role going forward. When asked about these characters, such as Deadpool and Legion, she said "I can't even go near that. That's in the future world, and that will reveal itself when we are ready to reveal it."
Legion airs February 8th, Wednesday, at 10 PM on FX. Be sure to check out the already released trailers in order to familiarize yourself as well.