The end of Mankind started in a blinding flash near modern Man’s own birthplace, in the Near East. The ancient, divided holy city was erased from existence by fundamentalists with a forbidden atomic weapon - a terrible act condemned the world over, even as regional fighting over scarce resources was becoming the new norm.
However, it was not the First Act that truly began the end. The bomb, with all its terrible power, was a mere pebble, dislodging to unleash a crushing rockslide. Weapons far worse than any man could imagine at the time were about to be unleashed in response. The Mad Prophet Abdul Alhazred later wrote thusly:
And He spoke with a voice like the shattering of the earth, and His words were searing light, and in the echo of those words we saw His true form, and He was not our God, but Theirs, and this was not our world, but a Shadow on the wall of Reality.
For in the years following the Unification Theory, man’s understanding of his very existence was fundamentally changed. What many expected to bring a paradise of clean energy, to be a solution to the resource scarcities and economic shocks gripping the globe, and to provide unique insight into the physical world, resulted in the opening of doors that should never have been opened - doors that could never again be closed.
The Dark Plane
The unification of all known physics explained many mysteries of the tapestry then known as reality. But with a single loose end, that tapestry quickly unravelled. For the first time in a laboratory deep under the Badlands of South Dakota, The Veil was parted ever so briefly, giving man his first glimpse of the Dark Plane.
It was hailed as the savior of first-world civilization. A dimension of pure energy, underpinning the fabric of reality - could that not be tapped to power our industry, to propel our vehicles, to light our homes? But a disaster of unknown origin occurred at the site of the initial discovery. The project was classified and all records were sealed, and the world was left in confusion and uproar. Surely such momentous knowledge must be shared for the betterment of mankind?
Not willing to fall behind in the greatest scientific discovery in generations, nations across the globe raced to start similar research, and all quickly discovered the same truth: this new dimension was not background energy waiting to be tapped. This was a Plane of dark, powerful corruption. Man peered into the darkness, and malicious intelligence older than our universe peered back. The darkness that spilled forth from the Plane warped the very laws of physics around it, and the creatures that followed were as hellspawn.
As many unfortunate researchers discovered, to look upon the Plane would destroy one’s mind. To expose the material world to it would unravel reality itself. The Plane was not a resource, not at first. Instead the Plane was the most potent weapon mankind had ever discovered.
An Opened Door
It was years later, after Jerusalem was destroyed, that the response came, swift and absolutely devastating. It was the first time the world had seen Dark weaponry, indeed the first time anyone outside the innermost circles of government and industry even knew such a thing could exist. Dark weapons, finely tuned to release Dark energy that would fatally corrupt human cells instantly while leaving all infrastructure untouched.
Not all life was ended though. Many on the edges of the blasts survived, changed, tainted by the Dark energy that played upon their forms at a subatomic level. They grew twisted and monstrous, walking empty streets, eating the flesh of the recently deceased.
Reality itself was corrupted as well. The Dark weapons thinned the Veil between this world and the Other, leaving Rifts between the planes. As outside teams moved in to assess the damage from the strike, mysterious and terrifying aberrations appeared near the Rifts. A hole of infinite blackness, floating in the air. Pavement and foliage transformed into indestructible metal of a type never before seen. A boiling lake with no identifiable source of heat. As the Veil slipped, physical laws as men understood them were cast out in favor of a new, alien reality.
Across the globe these effects appeared, cropping up after the first Dark weapon blast in an indecipherable pattern of harmonic Zones somehow linked through the Plane. Although the Zones were incredibly dangerous to explore, the resources they contained held promise for reality-bending Dark technologies. Soon nations were perfecting fantastic weapons capable of disintegrating matter, elements that could generate anti-gravity fields, and compounds that formed near-indestructible armor plate.
The Long War
Rather than solving mankind’s resource crisis, these Dark weapons fueled an arms race deadlier than any mankind had ever known. The Long War had begun. A hundred year descent into chaos, an unraveling of man’s lofty achievements, a dark century of violence where reality was torn by shadowy Rifts in space and time that scarred the globe. Massive social and economic upheaval, population crashes, and warfare of every kind transformed the face of the planet.
A century later the Long War still rages. a new era of unending warfare unleashed. A series of brief, desperate engagements over the span of a century, gradually grinding civilization to dust with increasingly terrible weapons, rending the fabric of reality irreparably and unleashing Zones of Dark Energy across the globe. Few of the Old Nations survive intact, either politically or geographically. The extent of the New Nations is determined not by treaty, but by the boundaries of uninhabitable Zones that cut haphazardly across old borders.
This is the age of the Legions. When war has torn civilization asunder and new empires rise, mighty Legions wield powerful weapons from before the fall of man, fighting in renewed struggle for control of a desolate planet, and standing watch over the shadowy rifts threatening to consume all that remained.