It's time for a fact-check: Was the X-Men villain Apocalypse really the first mutant? The apparently immortal mutant named Apocalypse was born nearly 5,000 years ago, in the days of ancient Egypt. He inspired fear even as a child, because of his strange appearance, but he soon fought him way to a position of rule. Apocalypse eventually retreated into the shadows, and has been a constant if terrifying presence in the world ever since.
Apocalypse considers himself to be the First Mutant, and Jonathan Hickman's X-Men relaunch has envisioned him as a champion of mutantdom. Apocalypse has taken up a new, albeit indecipherable, mutant name; it seems to be analogous to the letter A, a constant reminder that he is the Alpha of the mutant race. Amusingly, most readers seem to have bought into Apocalypse's propaganda, and as such they believe he's telling the truth. But was En Sabah Nur really the first mutant?
While Apocalypse is undoubtedly one of the oldest known mutants, he most certainly wasn't the first. The oldest known mutant is the woman called Selene Gallio, who possesses the power to drain the life from others. She was born 17,000 years ago in what is now central Europe, in the dawning days of human civilization. Selene is one of the rare mutants sometimes referred to as "Changelings," whose powers were active from birth rather than triggered at puberty. Her mother died in childbirth, and her tribe soon realized what she was. They believed Selene to be a dark god, and they conducted frequent sacrifices to keep the child alive.
In doing so, they unwittingly brought Selene up as a monster who saw others as nothing but food. She has continued to prey on others ever since. Selene has been responsible for countless tragedies over the millennia, opposed by Conan the Barbarian in the fictional Hyborian Age, burning down Rome, and reveling in the Black Death in the Middle Ages.
Selene is officially the first known mutant. And her very existence seems to suggest that there were others who predated Apocalypse, who were presumably the basis for legends of gods and monsters. It's true that there's been little specific evidence of them, but frankly that's no surprise; Marvel Comics' adventures are set in the present day, meaning only mutants who are functionally immortal would still be around. She and all these other mutants - including Apocalypse himself - should all be seen as evolutionary precursors, coming ahead of the main mutant explosion.
Apocalypse probably does believe himself to be the first mutant - but he's wrong. Ironically, both Apocalypse and Selene now live on the mutant island of Krakoa, and it's entirely possible the two ancient mutants will cross paths. It would be fascinating to see how Apocalypse would react to learning the truth - that he's not quite so special as he thinks.