What's going on in FX's Legion is difficult to parse out. There's telekinesis and ghosts of dead friends and government conspiracies and creepy men with yellow eyes? The first couple of episodes of Legion throw a lot at the audience but everything centers around the fact that David is a mutant in Legion. For a long time, David believed all the unexplainable things that would around him were caused by his mental illness, but he's getting more and more proof that he's actually one of the most powerful mutants on Earth. What exactly is a mutant in the world of Legion, though, and is he alone in his mutant-dom?
You wouldn't know from just watching the show, but Legion is officially an X-Men adaptation. Instead of focusing on as many X-Men as possible, like the films often do, Legion tells the story of one very unique mutant — David Haller. In Legion, much like in X-Men, "Mutant" is defined as a human (or other being) that possesses an "X-gene" that allows them to develop superpowers of varying strength and usefulness. Others in Legion seem to be of a firm belief that David is, in fact, a mutant — but like everything in Legion, it's tough to be sure it's not all just in his head.
When David is rescued at the end of the pilot, he's introduced to a slew of new mutants and learns that his beloved Syd was always a mutant as well. While David's powers haven't been fully explored, one mutant shows some impressive telekinesis skills during David's escape. While some mutations manifest in superpowers, others like Syd's powers end up seeming like more of a curse. As showrunner Noah Hawley told Entertainment Weekly, "If [Syd] touches your skin she trades places with you, her mind goes into your body and the other way around."
Joining David and Syd in mutantdom is Ptonamy, who Hawley revealed to EW is "a memory artist. He remembers everything, and has the ability to take people back into their own memories, and helps David get into his mind." One key character lacking mutant abilities? The mutant team's leader, Melanie Bird. "[Jean Smart's Character] is not a mutant," Hawley told the outlet. He also teased that there are more characters with different powers that will be revealed as the show goes on, opening up the writers to explore obscure and previously unadapted parts of the X-men universe. It seems that everyone in David's world believes he's a mutant, but of course there's a question of whether David's world is even real.
The line between where Legion's reality ends and David's mind begins is extremely blurred. It's entirely possible that the entire show is happening in David's head, which would be a very unappealing way to end one of 2017's boldest new show. Don't worry about David's mutant abilities being merely a hallucination, though, because there's one key scene in the pilot that hints that no matter what may be false, David is absolutely, 100 percent a mutant.
In one of the few scenes in the pilot to not feature David, two military officials reveal that they suspect that David is the strongest mutant they've ever encountered and consider executing him to protect themselves. While much of the show is filtered through David's perception, the military operation is incredibly realistic and far more mundane than the rest of the scenery in Legion. This scene tells the audience that the only thing you can trust is that David is a mutant. The reality of anything beyond that fact, however, is anyone's guess.