Warning: Spoilers for Giant-Size X-Men #1 (2025)!Legion, Professor X's evil son, is back as a bigger threat to the X-Men than ever before. Legion, or David Haller, is a character whose history dates back to 41 years, but his latest rebranding in X-Men lore re-frames him as even more powerful than he was upon his first appearance. Considering that Legion is among the strongest Omega-level mutants in Marvel history, that's not good news for the X-Men.

Giant-Size X-Men #1 marks the debut of Evil Legion, now equipped with a perfected version of Cyclops' optic beams. The difference between Legion and Evil Legion is that rather than being Xavier's son, Evil Legion is a separate entity. While David is still expelled to the White Hot Room, Evil Legion says that it's "what's left behind."

Being rid of his connection to Xavier rids Legion of any shred of humanity that has been used to defeat him in the past, rendering this new Evil Legion seemingly unstoppable.

Evil Legion Changes X-Men Lore Forever

"The Mutant That Walks Like a Man" by Jackson Lanzing, Collin Kelly, Adam Kubert, and Laura Martin for Giant-Size X-Men #1

When he was still Legion, early X-Men lore establishes David Haller as the son of Professor Charles "X" Xavier and Gabrielle Haller, a Holocaust survivor and Israeli Ambassador to the United Kingdom. Originally, it seemed as though David's birth stemmed from an affair that, as far as Xavier was concerned, never manifested a child, and he didn't know about David's existence until years after the fact. Powers of X, though, would heavily imply that David's birth was engineered by Xavier and Moira MacTaggert, looking for potential matches when they were in need of a reality-warping mutant for their mission.

David Haller's Legion debuts in New Mutants #26 by Chris Claremont, Bill Sienkiewicz, Glynis Wein, and Tom Orzechowski.

In any case, what's important is that the X-Men comics positioned David to be both a mutant powerhouse and a mentally disturbed individual. David suffers from an extreme case of Dissociative Identity Disorder wherein each of his alternate personalities has their own mutant power. The name Legion collectively refers to the alters within David's mind. Through the more deranged aspects of his mind, David was plunged into supervillainy, inevitably resulting in his death. One of his last appearances saw him enjoying his afterlife in the White Hot Room, assisting Nightcrawler from beyond the grave.

The New Legion Adopts the Power of Other X-Men

So Far, He's Seen to Have Cyclops Optic Beam Power

In the present day Marvel continuity, David Haller had become the X-Men's ultimate weapon, but in the past, a new version of Legion had traveled through time and space. The Legion identity is now represented by what was "left behind" by David's death. Time will tell exactly how this new version of Legion came to past or what he wants, but Evil Legion has already proven to be far more powerful than the earlier version by sporting a perfected optic vision straight out of Cyclops' arsenal.

What Cyclops shoots from his eyes isn't so much a heat vision as it is powerful beams of red energy, so powerful that not even Scott Summers can control his true power, hence why he wears protective visors at all times. By contrast, when confronted by a militaristic force, Evil Legion is immediately shown to know how to control his Cyclops-esque optic beams. Not only does he produce his eyebeams at will, but he unleashes them like a tidal wave of energy that wipes out everything in sight.

There's More Power to Evil Legion Than Meets the Eye

Giant-Size X-Men #1 Only Unveils a Taste, Including a Devastating Snap

Evil Legion doesn't stop at shooting a devastating blast at the army before him. As reinforcements and the remaining cavalry step onto the scene, all he does is snap his fingers to reduce his opposition to dust. As much as Legion has been shown to display overwhelming sets of powers, this seems like new territory even for him. It disposes of his adversaries with ease. It's also worth noting that the army were guarding what's left of the former Krakoa island, and with just one touch, Legion is able to send himself back years into the past.

The rest of his power can be seen as he fights off the X-Men and Kamala Khan. When Cyclops fires his own optic blasts at Legion, he's able to easily deflect them in the opposite direction. Furthermore, to neutralize Banshee's mutant powers, he muzzles his mouth with a web of spiders. In addition, with telekinesis, he can choke Ms. Marvel in midair without laying a single finger on her. Legion says he's not here to kill the X-Men, but he comes pretty close without even trying.

Evil Legion is an X-Men Supervillain Without Limitations

Anything That Held Legion Back Before is Irrelevant Now

Even as an Omega-level mutant, the Legion of the past always had a small setback, be it his own mind, his mutant abilities being subjected to separate identities, or even David Haller himself. David Haller is not inherently evil, and his run as a supervillain is a consequence of the Legion that uses his body as a vessel. It's unclear how much of David is still prevalent in this Evil Legion, if at all, but without that limitation, Evil Legion has nothing holding him back.

This is Legion in the purest form of evil that he's ever been.

Evil Legion has no drive to want to do good deeds or a humanity from Xavier talking sense into him. The X-Men's newest supervillain has his full mental faculties in order. He's still unhinged, but not deranged in a way that prevents him from carrying out his actions or regretting them. This is Legion in the purest form of evil that he's ever been. X-Men's villain roster sprouts some of the strongest antagonists in the Marvel Universe, but even most can be reasoned with or negotiated to. It looks like there is no such room for deliberation with Legion.

Ms. Marvel May Be the Only Key to Stopping Legion

X-Men's Newest Hero Must Control Her Power to Beat Their Newest Villain

At this point, the only way that the X-Men can defeat Legion is by pure force. When no one can lay a dent on the man, that sounds easier said than done, but Ms. Marvel comes the closest to phasing Legion. Kamala Khan unveils a new superpower upgrade that surprises even her, using it to connect with a swift punch to Legion's jaw. This is the first and only time in the comic that any of the X-Men lay a finger on Legion. Judging by his reaction of getting knocked back momentarily, it's an effective one at that.

Unfortunately, Kamala doesn't fully understand how to use, control, or manifest this new power at will, and so she loses the opportunity to follow-up with anything significant. However, as the battle rages on, she's going to need to learn how to master her new mutant abilities fast, as this may be exactly what the X-Men need to beat Legion once and for all. Otherwise, Evil Legion may conquer the X-Men and the timeline that he has invaded for nefarious gain.

Giant-Size X-Men #1 is available now from Marvel.