Legion is the illegitimate son of Professor Charles Xavier, who famously founded the X-Men. Raised by his single mother Gabrielle Haller in Israel, David grew up not knowing his father, who was similarly oblivious to the boy's existence for much of his adult life.
After becoming the Sole Survivor of a terrorist attack, the intense trauma sustained by David ultimately led to the manifestation of his mutant abilities — namely, the ability to absorb and cycle between distinct personalities in his head, allowing him to spontaneously develop their own mutations for himself to use. Because of it, David is one of the more visible avatars for mental illness in pop culture, and especially superhero fiction; whether or not this is a good thing depends on the reader.
Though initially introduced as an antagonist in New Mutants, David is often portrayed as an anti-hero more than anything else, and his moral compass isn't as easily defined as his father's — though Xavier himself is also prone to doing some seriously shady stuff.
In 2017, Legion became the subject of an eponymous television series on FX, portrayed there by Dan Stevens. This version of the character is a bit different from his counterpart in the comics, most notably because his connection to Professor X —and the X-Men mythos at large— is unclear, only obliquely referenced to. His struggle with mental illness is also emphasized, and plays a major role in the series.
Legion has appeared in:Notable Comics
- New Mutants vol. 1 (1985 — 1986)
- X-Men: Legacy vol. 2 (2012 — 2014)
- Legion (2018)
- X-Men: Evolution (2003), voiced by Kyle Labine note
Legion provides examples of:
- Acid Attack: His 762nd personality can breathe out a cloud of acidic green fog.
- Animal Motifs: In his solo, various superorganisms representing his mental state like bee colonies.
- Anime Hair: His iconic look gives him an Eraserhead-like tower of hair.
- Antagonistic Offspring: Towards Xavier at first. Since Xavier's death, David decided he wants to realize his dream, but using his own methods.
- The Atoner: One of his personalities, telepath Jemail Karami, was actually the psychic ghost of one of the terrorists who tried to kill him to begin with. After a while in the kid's mind, Jemail decided he'd been wrong and dedicated his existence to restoring David's sanity.
- Blessed with Suck: Legion sure won the Superpower Lottery... Except that David, the core personality, can't use the powers that belong to his splinter personalities, and that several of the personalities are nasty customers indeed.
- Breath Weapon: His 762nd personality can breathe out a cloud of acidic green fog.
- The Bus Came Back: After being missing from the end of Age of Apocalypse, David eventually returned during the Utopia era.
- Catch-Phrase: "Mine is the power of [insert personality/ power name he is currently using here]" in Legacy. His other one is "I rule me", which also serves as the Arc Words.
- Children Are Innocent: David's core personality is usually depicted like this.
- Combat Pragmatist: Sees no problem in cheating his way to victory.
- Combo Platter Powers: In a way, this is his superpower; he can create any superhuman power he can think of, at the drawback of having to create a secondary personality to control it. When he learns to take control of multiple personas for his own use, naturally, he can combine his individual powers in whatever way he pleases. Some of those personalities play the trope straight themselves by having distinct combinations of powers; examples include Absence (can siphon off heat and love), Kirbax the Kraklar (flight and electricity generation), and K-Zek the Conduit (wireless energy transfer and electricity absorption).
- Curb-Stomp Battle: He doles these out to enemies like paper flyers simply by the multitude of powers he possesses and his ability to use them when focused.
- Cursed with Awesome: Being mentally ill often helps him in his plans and enables him to concoct incredibly convoluted schemes.
- Deconstruction: His solo in X-Men Legacy has a number of jabs at usual X-Men conventions. The fact that they only find mutants with "flashy" powers, filling their ranks with combat capable mutations, the fact that they're so ineffective the X-Men still need to be soldiers, and that none of them seem to work on human-mutant relationships anymore like how mutants can not only coexist but also aid society.
- Defeat Means Friendship: After his defeat from the "New Mutants", Legion became their supporting character and unofficial member of the team.
- Enemy Without: In the first volume of X-Men: Legacy he seeks help of his father, Rogue, Magneto, Frenzy and Gambit, after several of his personalities escape. In the second volume, an evil personality modeled after his old man escapes and tries to destroy the world
- Embarrassing Nickname: David hates being called Legion. He says it's incredibly insensitive and tantamount to calling an epileptic superhero, "Spasmo".
- Famous Last Words: I was too bloody good for this place anywa..
- Fatal Flaw: In his solo series it's lack of trust. David is unable trust anybody but himself, so he manipulates people around him. As it turns out he is unable to trust even himself - this is why he personalized parts of his mind as alien beings and needs to fight to control them.
- A God Am I: Subverted in finale of Legacy - David merges with Weaver, becoming basically a god and starts fixing damage done by evil Xavier and himself. But then he realizes if he doesn't stop, he'll have to take control of the world and change it in his image. Which would go against all he believes in.
- Gondor Calls for Aid: Losing his final fight with Evil Xavier, David realizes his manipulative behavior alienated people from him so there is no one he can call for help now. Then it turns out he subconsciously sent his cries for forgiveness to all those people. And in response they came to help him.
- Guile Hero: In X-Men: Legacy vol. 2, David picked a habit of manipulating people for the greater good. Sometimes, might take it straight into Magnificent Bastard territory. Later deconstructed - the series makes it clear the people he manipulates either see him as just a dangerous, unstable individual or an outright Manipulative Bastard, so while he gets the job done, he utterly fails at making any friends.
- Many Spirits Inside of One: He had multiple personalities with different superpowers. Then he went better, but as a whole was so powerful that he caused the Age of Apocalypse. He later came back, now having hundreds of personalities, each with its own unique power. Some of them are minds of dead people he drained, making him a combination of this trope and Mind Hive.
- Mental Affair: Has one with Ruth at the end of his solo series.
- Odd Couple: With Blindfold in Legacy.
- Papa Wolf: In Legacy David becomes protective of children and firmly believes the fact young mutants still have to learn to defend themselves proves X-Men failed to accomplish anything.
- Plot-Relevant Age-Up: In his solo series his core personality grew to his actual age.
- Power Parasite: Played with. In his solo series he learned to have his core personality drain the powers of his other personalities, allowing him to use them himself without having to cede his body over to that personality, and to combine powers from different personalities.
- Psychoactive Powers: However, how strength his core personality depends on his own confidence or determination - if he allows himself to be consumed by doubt, he barely can drain weakest personalities. When he really gets his head set on something, he can get the strongest ones. after David learns to merge with his personalities, high confidence allows him to do this wih strongest ones
- Punny Name: Cyndi (cinder), the pyrokinetic personality.
- Reality Warper: The most powerful of Legion's personalities, including the ones that are more or less cohesive amalgamations of his shattered psyche, have the ability to change reality itself in wide-sweeping ways, to the point of creating an entire alternate universe during Age Of X storyline.
- Ret Gone: In the end of Legacy he wiped himself from existence in the 616-world, the sole person remembering him being Blindfold.
- Split Personality: Varying in number; originally it was just three plus Jemail, but things have gotten... complicated.
- Superpower Lottery: Telepathy, telekinesis, pyrokinesis... too many things to count... Taken Up to Eleven in the "Age of X" storyline, where he goes and creates an entire universe.
- Superpowered Evil Side: Jack Wayne, among others (Jack was not the only malicious personality, but he did take over several of the others' powers at times, making him the most dangerous).
- Tomato in the Mirror: All his personalities are aware they're in his head, but most of them believe they're real (which given David's abilities, might be true). At the climax of his solo, his most powerful personality, the Great Weaver, reveals it has his face and its dialogue implies that David is the errant ego running around with his body.
- Unwitting Instigator of Doom: During the 90s, Legion traveled back in time to kill Magneto, reasoning that his father would have a better life if Magneto hadn't been there. Unfortunately, Charles took the fatal blow for Erik, and the brawl itself woke up Apocalypse several decades early, creating the Age of Apocalypse
- Villains Act, Heroes React: In his solo series he becomes critical of this approach and tries to be more proactive kind of hero by removing enemies before they become more dangerous.
- What Happened to the Mouse?: Jemail Karami seems to have vanished entirely.
- What the Hell, Hero?: Oh so very often in his solo series. Pretty much everyone from Blindfold to Pete Wisdom to Aarkus calls him out on his manipulative ways. Except for Pixie, Chamber and Frenzy, who skipped that part and just beat the living shit out of him.