"Welcome to hell. Or earth, whatever you want to call the damn place. Most of us call it home -- though we ain't kind about the name or place. Some fellow once wrote that the cradle of man had become a killing ground. He should live here now. Corps run the world, with Gangs in charge of the hot spots Corps avoid and the rest o' us just try to live, caught between the rocks and hard places."
- From the Unofficial Tourist Guide to Earth, p ii
Earth is currently a vast sprawl of ruins. While the ozone layer was healed once, mankind has abandomed their womb for other worlds. They left the lawless, the cripples and the mad behind -- and these peple have shaped the earth and changed it. As one historian put it "The histories we write are very nice, but more for what they do not say than what they do." History tells us we left Earth for Asgard; it does not tell of those we left behind. Asgard is situated in Alphas Centauri, 4.2 light years from Earth -- and over 40 years travelled in 4 subjective years moving at half light speed. They were away from earth for over 100 years, and in that time it became a lawless wasteland, technology lost or brorken or abused to create genetic mosters called mutants.
For some reason, shortly after the bulk of mankind left Earth, there was an uprising among those left behind, a war for governance. The result was a literal bloodbath; over 5 billion people of the 10 billion people on earth died, the War of a Hundred Suns lit the sky with nuclear rain amd people huddled in shelters, fearing the end of the world. It took 50 years for the people to come back to the surface, and find it a toxic waste. Robots, obeying order given over sixty years ago, built cities and buildings over ruins, creating an urban nightmare that makes Mexico look pretty by comparison. Only a few corporations survived the war and the 50 years underground. They are the only powers left on the world, the only scientists left behind passing their knowledge down to chosen successors and keeping the world running.