Ross designed a future where all ordinary humans had gained superpowers, and he examined how some of the most well-known Marvel characters (including Spider-Man, Captain America and the Incredible Hulk) would manage a world where their superhero powers had now become commonplace.

About ten years after the end of the heroic age, Black Bolt releases the mutagenic Terrigen Mists into Earth's atmosphere, seeking to transform humanity into Inhumans so that his people would not suffer persecution.

Unable to operate his observation equipment, Uatu transports X-51 (Machine Man)—who has long since given up super-heroics to imitate the life of his human creator—to the Moon to act as Earth's new Watcher.

The Terrigen Mists begin mutating Earth's human population, though much of the world blames "Plague X" on Richards' failed experiment.

Norman Osborn manipulates America into electing him President by using alien DNA to create the Hydra—a parasite collective that mind-controls its host bodies.

Osborn grants Tony Stark (one of the last unmutated humans) political asylum in exchange for constructing robotic replicas of the fallen Avengers to battle the Hydra menace.

Loki realizes that he was only the evil son of Odin and a Norse God because when he evolved beyond his mortal form his psyche became a tabula rasa.

As the Celestials prepare to attack New York, Loki arrives with a host of Asgardians found in the afterlife and announces he's not bad because he formed the Avengers.

Black Bolt is killed after using his voice to travel across the universe and call for Galactus, who is revealed to be devouring worlds in order to destroy Celestial embryos growing within them.

Reed Richards also realizes this fact and makes the heartbreaking decision to not remind Franklin of who he originally was for the sake of the universe.

X-51 realizes the Watchers' true purpose is to watch over Celestial eggs because one of their numbers failed to stop the birth of Galactus millions of years ago.

With the Celestial embryo gone, the Earth's mass is reduced, causing a shift in orbit and polarity as well as drastic worldwide climate changes.

Under Mephisto's influence, Pope Immortus founds a church advocating mutant dominance of the galaxy and the destruction of Reed's Human Torches.

Captain America becomes the Mar-Vell child's guardian and embarks on a worldwide quest with his new ward to obtain various items in order to deal with Earth's restless mutant population and prepare for an impending war in the Realm of the Dead.

Arriving at Zero Street, the duo is attacked by the Night People, and Captain America sacrifices his life to save the Mar-Vell child.

But as more souls enter Paradise, it begins to expand and consume entire worlds within the Negative Zone, causing Blastaar and Annihilus to attack the Baxter Building in New York.

They decide to access the imprisoned Jude the Entropic Man, who can turn others to dust on contact, and synthesize his essence into a chemical to end the suffering of those unable to die.

With the chemical complete, Reed, growing suspicious of Mar-Vell's motives, plans to use Pym Particles to slow Paradise's rapid growth within the Negative Zone.

With the help of Merlin, Doctor Strange, Psylocke and the sacrifice of a recently resurrected Meggan, King Britain is able to slay Mephisto with Excalibur.

Feeling that his work is not yet complete, Mar-Vell tells the people of Paradise that he is going to the source of Excalibur, which is strongly implied to be the original universe.

[8] Initially, the Earth X storyline was purported as being the future of Earth-616, but the series often substantially retconned the origins and workings of characters to better suit the story, to the point where they were no longer reconcilable with their counterparts in the mainstream Marvel Universe.

One example is the revelation in Paradise X that Wolverine is not a mutant, but instead one of the few remaining "pure strain humans", free from the genetic manipulations of the Celestials (as well as a descendant of Moon-Boy).