Over five hundred years ago, humanity began colonizing outside of our Solar System. For nearly two hundred years they spread amongst the stars and even discovered several non-intelligent life forms, but one thing remained clear; Earth was special, perhaps unique, in it’s biodiversity.
Then one day humans encountered a host of intelligent races, all fleeing from a war-like race that became known as the Elves. Humanity welcomed these new races, and prepared to meet the Elves in battle. Elves had powers that could only be called magic, and while humanity fought well, they were no match for forces they could not understand.
The Elves destroyed all of the human colonies and eventually conquered Earth. Some humans escaped along with many of other races we had encountered, but most were enslaved by the elves who used them to harvest Earth’s biodiversity.
Humanity formed a resistance movement, and eventually uncovered the secret of Elven magic—nanotechnology. Humans injected themselves with this technology and were able to use magic. Despite this, humanity could not defeat the Elves, and eventually a weapon of mass destruction was unleashed; the Planar Instability Device.
This device caused several alternate planes of existence to overlap Earth. Elements of Earth appeared in these other planes, and elements from these other planes appeared on Earth. The atmosphere was changed and a host of new life forms emerged. Many of these were intelligent, and some were powerful beyond comprehension. Chief among them were the 7 Deities, the Archfey, the Fiend and the Great Old One.
The earth rebelled, and many earthquakes and eruptions occurred. Tsunamis struck every shore, and fires raged out of control. In the end, the changes in Earth turned it into a wasteland, and eventually the Elves lost interest. They left a significant army behind along with enough firepower to at least prevent anyone from leaving the planet, and then they moved on.
That was well over one hundred years ago. The Elves mostly leave people alone, except in cases where they feel someone is becoming too powerful and might become a threat. While Earth still has a wide variety of life, it can’t sustain the quantities it once had. Populations remain low, as do resources. People of all races fight over food and resources; slavery is a common practice, and in most places the rule of law is Might makes Right. It is a harsh world with little of its former glory.