This review contains spoilers for the series finale of Legion, aka Season 3, episode 8, “Chapter 27.”
It’s hard to know what to say about a series like Legion ending. There’s an impulse to wax nostalgic on the sum of its parts; to gloss over the bits and bobs that do not work in order to consider whether the plane was or was not well-landed. Does it all just come down to the ending, after all the complicated, wildly outlandish, and totally kookaroo stuff we just watched over the last three seasons? Did any of it matter? Was that entirely the point?
Legion’s goals were always simultaneously simple and wildly complicated. Series creator Noah Hawley wasn’t interested in telling a typical comic book origin story — he just wanted to have some trippy, existential fun with a bunch of incredibly game actors. This is why the story of David Haller appealed to him: the son of Professor X/Charles Xavier is the most powerful mutant of all time, but no one knows where his powers truly originated. Were they because of his father, the monster in his head, or the mental health issues that seemed to swirl around the lot of it? It wasn’t so cut and dry. It was a dissection of creative talent and mental health: how much of the control over these things actually belongs to us? In this world, the usual social binaries need not apply because our hero was actually a superpowered villain who really just wanted to be good. And so…our deliriously tripped-out journey into David’s mind began, and began again, and restarted, and got turned over on its head and sent on a quest for control and dominance between a “bad guy” and a “good guy” who were slowly trading places.
Source: IGN.com Legion Series Finale Review