Marvel Comics once decided to give one of its most powerful villains, the Beyonder, a shocking new origin, connecting him to mutants and the Inhumans. However, over time, the retconned history of the reality-manipulating villain has been forgotten - as it was later revealed the Beyonder was just one of many Beyonders, an alien race who are responsible for the different Secret Wars that have pitted different realities against one another.
The Beyonder made his first appearance in Marvel Super Heroes Secret Wars #1 by Jim Shooter and Mike Zeck, as he assembled the greatest heroes and villains from across the cosmos to fight on Battleworld. Described as the most powerful being in the Multiverse, Beyonder used his immeasurable reality-warping powers to create future Secret Wars and make Marvel's most powerful entities look weak in comparison. However, Marvel Comics retconned the original Secret Wars in New Avengers: Illuminati, where it was revealed Xavier found out the true Inhuman history behind the Beyonder, which also tied the villain to mutants.
In New Avengers: Illuminati #3 by Brian Michael Bendis, Jimmy Cheung, and Mark Morales, Professor X revealed the true nature of the Beyonder. In the issue, Xavier reveals during the original Secret Wars, he used his powers to look inside Beyonders mind, which showed him the Beyonder was actually an Inhuman - and not only that, but he was also part mutant. According to Charles Xavier, he had mutant genes before the Terrigen Mist unlocked his full Inhuman nature.
Later, the Illuminati met with the Beyonder, where the all-powerful being bowed down to Black Bolt, revealing his allegiance to the Inhuman Royal Family. The moment eventually references Black Bolt talking down the Beyonder during Secret Wars II, as he vanishes in front of the heroes.
So, is the Beyonder is an Inhuman-mutant hybrid? Well, that's where things get complicated. In New Avengers #30, the Beyonder's backstory was retconned again. Marvel explained the Beyonders were an all-powerful alien race and the Beyonder encounter during the Secret Wars was a child who visually modified itself to its surroundings. So, the Beyonder they met likely misled the Illimunati on its true nature.
While the Beyonder's second retcon made sense, making the villain an Inhuman-mutant hybrid made for a somewhat perfect origin. He showed the true powers of the combined Marvel races and represented the best and worst of the great abilities. The Beyonder tied the Inhumans and mutants together. But, ultimately, Marvel Comics decided the retcon of Secret Wars was too much and retconned the Beyonder again and forgot his Inhuman-mutant origin.
