I'm working on expanding my old homebrew RPG setting, and it's definitely gone through some refinements since a friend and I began to come up with it. The basic idea is that it's a setting that diverges from Earth some time in the 19th century. In this setting, the Earth's core is actually a magical dynamo that produces Mana but is usually constrained by the layers of magma and rock that encircle it. The invention of widespread oil drilling led to large amounts of Mana being leaked out, enabling humans to manipulate magic and jumping science to a level beyond even modern-day science. Unfortunately, leaking all this Mana was ultimately a destabilizing element, and over time the magical dynamo grew unstable. Ultimately, this resulted in an Earth-shattering explosion, rendering the planet into a network of habitable chunks orbiting the Earth's core. Everyone more or less knew it was coming, and the "races" of my setting all stem from various groups that survived in various ways. The Races: The Technocrats - Aristocratic clockwork liches, more or less. Basically, all the world's rich people left on big spaceships and waited for the dust to settle. Problem is, their machines didn't work so well the farther they got from the planet, so they had to get rid of life support. By the time they return two centuries down the line, they're borderline alien clockwork robots who want to reclaim their holdings. The Humblekin - Dispossessed Druids. Made up of the poor and working class, various disparate groups of people managed to eke out a living protected by particularly gifted magic users from among the poorer classes. Over time, this reliance on "wild" magic led them to abandon technology and more or less become the wood elves of the setting. They come in different flavors and don't represent a unified faction, so the Humblekin in Moscow are different from those in Glasgow or Los Angeles. Some just want to break stuff, some want to carve out empires, and some want to be left alone. The Jade Alliance - The Dwarves of the Setting. Made up of most of Asia, the Jade Alliance was a pre-catastrophe trading-pact that evaded the catastrophe by hiding in underground complexes, some of which survived the shattering. Unlike the Technocrats, their technology continued to function and develop, though the culture that sprung up during the centuries underground eventually came to resemble an odd mish-mash of Islam and Confucian ideals. By the time they come topside, they're ready to start re-forming society and establishing trade routes once again. The Ancients - African Elves. Unlike the others, these groups largely survived unscathed, the native faiths resurging and taking the advent of magic well, able to shield their territories by guiding the energies away. Once the shattering had settled, the various groups were united by the Neo-Egyptian Ancients into a stable empire deeply rooted in magic and tradition, seeking to unite the rest of humanity peacefully. Along with these groups are various beasts and uncategorized species, having been changed and mutated by the huge amount of Mana that was released during the shattering. While the non-Technocracy groups did manage to survive relatively unharmed, they did change enough to form their own subspecies of human due to what Mana leaked through. The Humblekin tend to be gangly and long of limb, average height around 6' as adults. The Jade Alliance tend to be 4'6 or so on average and are very stocky. The Ancients remain largely unchanged, with pointed ears being the one notable exception. Now that all the groups have emerged from the Shattering, the four major powers are officially at peace but all of them are jockeying with each other for territory to reclaim. Travel between the floating planet chunks varies depending on who owns it and what group you belong to. Technocrats might have some ridiculous chariot pulled by robotic pegasi, Humblekin would conjure up giant butterflies to ride, Jade Alliance would probably just build a bridge or fly a plane over, and The Ancients would magically pilot ships from place to place. Though these are the major powers settings and motivations, there are nonetheless civilians and individuals that do not necessarily act the same. There are nice Technocrats and evil Ancients, and most people from every group are just meta-humans trying to survive. As such, there is plenty of room for small-scale adventuring groups and big-scale political intrigue as well.