This X-Men Character May Be Too Powerful To Ever Join The MCU

Ask any Marvel fan which of the sprawling entertainment giant's many characters is the most powerful, and you're bound to stir up a debate. It's a hard subject to narrow down to a few select characters, even when you're simply discussing who in the Marvel pantheon is the most powerful. 

Thanks to the longevity of Marvel's publishing history, there are dozens of characters with downright stupendous powers who have yet to show up in the MCU. Some would point to characters like Molecule Man, who, after being irradiated, can manipulate any object — sentient or not — on a molecular level. Others, like Lady Death, hold so much sway over certain characters (in her case, Thanos) that their very presence could unravel potential storylines and sow further chaos in already fraught locales. Innocent young Franklin Richards can warp reality with his mind. Elsewhere, fans might go to bat for characters that already exist in the MCU, such as Captain Marvel or The Silver Surfer.

Let's focus on one particular superhero team: Marvel's X-Men. The X-Men have become legendary in the pop culture sphere since its 1963 inception (per The Encyclopedia Britannica). Not only do they reign supreme in the comics world, but the "X-Men" film franchise has become a foundational franchise in the superhero tentpole genre. Add to this the fact that fans are curious about the future of the X-Men in the MCU, with recent attention on a possible X-Men sighting in "Doctor Strange in the Multiverse of Madness" trailer, and it seems hype for the mutants is hitting new heights.

As we consider which X-Men will be the first to make their MCU debut, we know of one who is so powerful that their existence makes them a very unlikely candidate.

To put it simply, Onslaught is Professor Charles Xavier and Magneto's mind baby. However, if you want to get technical, Onslaught is a sentient creature created by the two mutant leader's psionic connection (via Marvel). Onslaught's conception occurs when elements of Xavier's darker nature combine with Magneto's hostility thanks to a mental link Xavier establishes to push Magneto into a bout of catatonia so he can wipe his ex-friend's memory. Professor X is subsequently pushed to the breaking point by events in his life, which causes Onslaught to emerge as a sort of alternate personality for the normally sensitive team leader.

Seemingly confirming he is definitely the result of a coupling of Professor X and Magneto's powers, Onslaught chooses to bring humanity together in harmony by "improving" them — by melding them into a singular conscious. He tries to do this by using interdimensional law firm and holding company Landau, Luckman & Lake's warp portals and seeking underground support for his cause from criminal figures like Juggernaut. In an early display of his might, when Juggernaut refuses to help him, Onslaught wipes his memories and teleports him all the way to New Jersey in a show of psionic force.

The X-Men become aware of Onslaught's plot when he tries to create his own Sentinel army. Subsequently split from his host, Onslaught can now operate on his own whims. Cloaked in nearly-indestructible armor and fearsome in his gigantic form, he recruits a team from the best of the X-Men rogues gallery. He tries to convince the X-Men to join him in his quest to destroy humanity, and when they refuse, he turns his aggression toward them and their allies. In the end, Onslaught's might nearly takes out the Avengers, the X-Men, and the Fantastic Four, but a team effort ultimately vanquishes the might mutant.

It's hard to deny that the notion of an "X-Men" film or an entire MCU arc centered around Onslaught would be thrilling or, at the very least, quite compelling. He's one of the X-Men's most powerful villains and nearly succeeds in destroying the entire X-Men team. In fact, he actually manages to use them and Franklin Richards as sources for his own psychic power. It's only thanks to Richards that the other mutants survive when he transports them to a pocket dimension.

But Onslaught is so powerful that it takes a huge, cross-Marvel effort to kill him, with three different super teams working alongside villains like Doctor Doom, as well as ordinary citizens. This is a being who can create an entirely new sun in the hope of broiling humanity to death, all because he thinks they're not worth saving. He knows how to manipulate the vulnerable, tricking Franklin by posing as a child named Charlie and feigning friendship with him. He uses his psychic energy to control hundreds of Sentinels. It takes a combination of a Hulk, with his humanity held in check thanks to psychic interference from Jean Grey, and Thor on a rampage, plus many others, to reduce Onslaught from a physical form to a psychic current; that's a lot of manpower. If you put Onslaught into a film, any ending you use would have to explain how a superpowered character like him might lose against a weaker hero.

It might put you in mind of that last scene in "Avengers: Endgame" where the entirety of the MCU gathers to take Thanos down, and perhaps someday we'll get an X-Men version of that moment. One never knows.