When Astraea, the planet, formed the races that learned to work together all did so and banded together in union while the other races that were selfish, malicious, or unwilling to adapt were eventually destroyed. The Union races went on to build a utopia and everyone prospered. Their problems all being solved through the unity of many different people who are willing to work together. Then they built. Built more, built bigger, built brighter, ever reaching towards the stars above. A rapture of fascination among the Union was exploring the great beyond and setting up other worlds to also be utopias for their enjoyment.
They built up and up, layer and layer, and eventually they touched the crest where the sky meets the stars. From there they began making large platforms hovering in the low gravity of their planet with minimal effort and on those platforms they did what they always did. They built.
They built an armada, because they had little else to do as a Union they were able to amass an impressive labor force that all wanted to help touch the stars and thus they didn’t build a single starship, oh no, they built fleets.
Then the day came when they launched their flagship into the stars for the first time and everything went wrong. The ship disappeared alright but left behind the Laceration, the first of many. Time and space went awry and the energy burst from the flagships departure caused a chain reaction and every ship in the armada plummeted down to the upper layer of the planet taking with them the massive platforms used for their construction still littered with supplies, worker camps, buildings and more.
This caused the whole world to shudder as their infrastructure collapsed.
Now the world is attempting to rebuild, but the golden era is lost. So many people have died or been cut-off from society that panic arose and in-fighting began. Those in and near the core locked it down in fear and now live in a relative heaven compared to the rest of the planet. With control over the oxygen and food those that tried to break-in were quickly broken. Those in the core aren't cruel or even selfish however, and continue to maintain the core full of green and they continue distributing as much food as they can and continue maintaining oxygen throughout what remains of their infrastructure. Only ever cutting off supplies when under direct duress. Nova-9 is a layer on this world. It is full of ads, shops, markets, food stalls, and sells virtually everything. It is also a popular hub for the mercenaries, or Star Runners, as sometimes called by the locals, that has become a popular profession since the event of The Laceration, or the L, the term for the apocalypse of the ships crashing down. The upper layers have become dangerous with societies cut-off from oxygen and food finding new ways to survive. Fighting amongst each other in deadly gang conflict for scraps typically, preying on those travelling the Star Roads, or whatever else they can because they have been cut-off from the food and oxygen of the core for so long they have no choice. Raids on lower levels are beginning to ramp up as those near the stars become more savage. Terrifyingly enough, they are not alone however. Strange entities born of the Warp they created so long ago with their failed launch have caused an interesting mix of alien-like entities that are spreading through the cracks and crevices left in the wake and they are hungry... The players play Star Runners, and have adventures exploring the ruins of their previously advanced society. Bringing home the goods they can trade for a better life closer to the core, and gear to survive their next trip to the Star Roads.