The Torn Filter - Legacy of the Omnire
The Ancients were the first to pass through the Great Filter, just barely surviving their wars long enough to leave their homeworld for the stars. They spread like the invasive species they were, their self-replicator swarms devouring entire worlds to build habitat clouds around stars. Each and every species that now inhabits the galaxy was uplifted by them, absorbed into their own culture. After the Ancients conquered the galaxy, there was no more filter. They had torn it apart.
It was the first and only Type 3 civilization, harnessing the power of a hundred billion suns for its own use. Nations with populations in the trillions were not even worth a footnote in the history books, massive civil wars could take the lives of just as many without ever being noticed by those elsewhere in the galaxy. Great colony fleets were sent out into the intergalactic void, countless thousands every day, seeding the universe. The trillion stars of the local group were made theirs.
The very laws of the universe were twisted to the will of the Ancient magics, and the gaps between gravity pockets were bridged by another wave of colony fleets. All things became their domain, and all was made into one nation in the Great Unification. The Omnire, a nation spanning the entire known universe, was formed. For a time, all was peaceful. There were no more wars, not even tiny skirmishes. A number of individuals inconceivable to the mind, united under one banner.
No such accomplishment could last.
The War began. It was given no name beyond that, for any name would be inadequate. It was the only war that ever mattered. The entire Omnire erupted in war, every star of every galaxy of every group of every supercluster became a battleground. It went on for millions of years, every second countless battles raged and in each of those battles a trillion died. Entire planetary campaigns were nothing, and billions were won and lost every day. The previous wars between collections of habitats and star systems paled in comparison.
New weapons were created at an alarming pace, with their designs being distributed instantaneously through the networks and hive minds of both sides. Warships the side of solar systems clashed in the millions in the dark space between galaxies, and those galaxies themselves were hurled at faster than light speeds toward the enemy. Whole superclusters were swallowed up by magical weapons that tore apart the very fabric of space and time. It was a war that those alive today could not possibly imagine the scale of.
When all was said and done, the Omnire was completely eliminated. The bindings between galactic clusters, set in place by the Ancients, crumbled and the universe was lost to redshift. The once-glorious superstructures the Omnire had constructed now lie in ruin, their former populations slaughtered.
It has been billions of years since The War, and the local group they once colonized has merged into a single supergalaxy-. Its inhabitants are unaware of each other and The War, their only knowledge of what transpired reserved to the feeling of loss and unease when they look upon the ruins of a Dyson sphere. With the fall of the Omnire came the fall of civilization, the apocalypse wrought by The War ending all life. Now, upon the ruins of their habitats and Dyson spheres, there emerge new civilizations.
But there is no longer a filter. The knowledge of space travel and magic was known to these new civilizations since their earliest days, and so they survived their wars. These civilizations spread out throughout their home systems as the Ancients once did, scavenging from the ruins of the Omnire and building their cities upon their dead bodies. Now, they have begun to reach out further into the Galactic Pangaea. Unlike the civilizations of the ancient times, they will meet on equal terms.
Only time will tell, however, if they will not fall to the same fate as the Omnire.
This RP, as you might have gleaned from that block of test, won't take the usual form of a sci-fi NRP. There are ruins quite literally everywhere, not just a few remnants as in other "The big empire fell once" stories. There are also no survivors at all, all sapient life from before The War was killed by it. Some of the species that will appear will likely be related to the Ancients, be it through old genetic engineering projects or just happening to have evolved from the bacteria in their digestive system.
These civilizations have also had the ability to travel through space since before they invented nuclear weapons, whether that means they figured it out around their version of WWI or their version of the Punic Wars is your decision. Plenty of them will have probably evolved on ruined habitats, still-habitable parts of Dyson spheres, or other ancient megastructures. Please don't use this as an excuse to give your Space Orcs ten trillion warriors. Remember, it's been billions of years and a war destroyed just about everything. Any remaining megastructures will be banged up to the point that they won't be fully usable. A Dyson sphere would have only a fraction of its surface be habitable, for example.
Magic, in the form of Ancient arts, does exist. It is more akin, however, to the Force from Star Wars than most fantasy magic (though it does just about everything bog-standard fantasy magic does anyhow). Using it involves not chants or spells, but the application of extremely advanced mathematics to calculate how to best manipulate the unseen force the Ancients created. It doesn't abide by the laws of physics, so you can just create matter and energy with it however you like. Remember, the Omnire controlled quite literally all that exists and changed the laws of physics to keep the universe from expanding. Manifesting a fireball is nothing.
Those calculations can be handled by either Ancient devices, most likely computational crystals that don't need any energy input because, again, Type 4 civilization. What I'm saying is you can totally have a wizard with a crystal staff if you want. Alternatively, your own civilization could have constructed computers to do the calculations and emulate the crystals. Even for a species that has figured out quantum computing pretty well would need to have a huge complex to do this, however.
The magical power itself is accessed through any living being, since the purpose of the power's creation by the Ancients was to make every individual capable of feats that would otherwise take a small country to accomplish. Note that this means some species could have evolved to be capable of the necessary calculations without the help of a crystal or other computer, and those species could be anything from magical beasts to your own civilization. Just keep that to a minimum, because there's really no reason that should be the case at all beyond cool factor.
It's worth noting that this means that civilizations from habitat or megastructure ruins would actually be less "technologically" advanced and more "magically" advanced (even though magic is just hyper-advanced technology here). This means that you could have a civilization comparable to medieval Europe that can still avoid being steamrolled by one comparable to modern humanity, since their use of magic would let them fight toe-to-toe. Magitech civilizations are also entirely possible, depending on how you decide yours developed.
As for just what sorts of megastructures you'll run into/come from, there's no actual limit. The Omnire didn't care for efficiency, so relatively silly ones like an Alderson Disk would be entirely reasonable. The only constant is a clear indication that something created it and that said something is now gone. Go crazy. I want to see Ancient Ecumenopolises, starlifting facilities, whatever you can come up with the Ancients could have built.
There's no real NS template, but a few of the things that are essential for it are:
-History (Of both species and nation. Tell me how you evolved, not just how you united or failed to unite).
-Extent/territory (How widespread are you, what's your rough population? Be balanced here. The backstory might involve a Type 4 civilization where everyone is a demigod, but that's not what the new civilizations are).