Scavengers of the Latter Ages

art by Shahab Alizadeh

Here are some further refinements/elaborations on the idea I presented in a previous post for a 5e (or any sort of D&D really) game that was actually far future science fiction replicating fantasy.

• The Distance Future: Millions of years certainly, though exactly how long is obscured by the mists of time and the humankin's fickle devotion to data storage formats. It is possible that biologic humanity even disappeared at one point but was resurrected by its nostalgic offspring. Scholars are aware that more than one civilization has come and gone and the Height was long ago.
• A Neglected Garden: Earth was once an intensively managed paradise, maintained by nanotechnology and AI that were integrated into the natural world. Most of the animals were heavily modified by genetic engineering and technology, and some were of exozootic stock. Even humans were integrated into this network, and everyone born still carries the nanotechnological  system within them. Though technological spirits and godlings still live in nature, they no longer heed humans on any large scale, at least in part due to the fact that few humans can activate the necessary command codes.
• Diverse Humankin: Through genetic engineering, different clades of human-descended biologics have developed. The reasons for the modifications from baseline seen in these "races" may not always be apparent. Perhaps some were just art projects for some creative god?

Art by Laura Zuccheri

• The grist: Commoners speak of "magic users" in dim memory of the fact that everyone of Earth is a "user" in the computer science sense, but wizards know there is no such thing as magic, only grist, the layers of nanotechnology that envelope the world. Everyone uses it to a degree, but few have the aptitude to develop the skill to employ the grist to work wonders.
• The ether: The underlying grid of spimes and metadata, which supports the nano and once integrated it with the internet, is known as the Etheric Plane or Ether. Wizards and other magic users are aware it plays an important part in their spells and also in the powers of gods and incorporeal intelligences, but they are like mice within a palace, ignorant of its total function and potential.
• The Outer Planes: Civilization at the Height was not confined to the Primal Earth, but extended through the stars. Some of the posthumans that went to other stars disassembled planets to convert to computronium, then huddled close to stars for power. Their civilizations sometimes became very strange, perhaps even went mad. Many of their networks still connect to Primal Earth through ancient but robust relays. Humankin of Earth are often in grave danger when they venture into such places.
• Treasures Underground: Earth's current society is built on the detritus of millennia. Current humankin seek to exploit it in rudimentary ways, and more advanced civilizations of earlier times sought to do so in more advanced ways. The tunnels they dug still exist, but so do the guardians they put in place and the dangers they encountered.