Below, you'll find a short summary of what happened in Tyrrhenia's history to bring it to this point. It is written to be very short and easy to digest, so it doesn't necessarily go too much into detail. Most characters will have some vague idea of how this is said to have gone.
Across Tyrrhenia the weather had gone insane, causing massive natural disasters, well beyond the scope of what Tyrrhenia was prepared to handle. Ecosystems began collapsing, and Tyrrhenians began dying off in scores. Soon, there was enough ash in the atmosphere to trigger anti-greenhouse effects. The planet's surface cooled, destroying a number of the flora and fauna. Food rose in price, and everything else soon began costing more. Many died of starvation, businesses shut down all over the world, and more died soon after.
It was not a sudden collapse, the End, but more of a steady, gradual decline, an unending string of misfortune.
Some governments attempted to implement martial law, but by then, it was too late. As more jobs collapsed, more people died, food continued to skyrocket in price, and finally, the internet crashed, the people soon turned on their governments and police forces, tore both down, and then turned on one another.
The humans on the surface, however... well, no one ever heard from them again. It is assumed they eventually killed one another, died off, or both.
However, one group never did fade away. The United Republic gathered together and solidified their presence, and came up with several different ideas that would perhaps allow Tyrrhenians to return to the planet's surface, where they belonged. They designed, and later began building, a massive dome, constructed of solid supports and strong barrier shields. The dome was designed to be a climate-controlled area, protecting from natural disasters, crazy weather patterns, the sun's now-harsh rays, and anything else that may be up there. Upon scoping out a place to build the dome, the Republic discovered strange begins inhabiting the planet's surface; the first to see them called them demons, but now they are called Others.
The Republic designed and built the first daeni, not very intelligent robots that were tolerant of the planet's inhospitable surface. The dae slowly replaced the human construction workers that were building the Dome, and finished the design. The dae remained useful after the Dome was built, too, as they were very knowledgeable of how the Dome worked, and were given new Artificial Intelligence programmes, that they could fill a variety of roles.
Humanity returned to the surface. As the Dome flourished and proved a success, the other Homes' inhabitants moved to the Dome, too. Livestock were cloned and plant-life was revitalised.
Humanity was on the verge of a resurgence.
In time, the Republic sought a peace with the Others. The Others didn't seem to have the same interests. Now, one is either human, or Other, and the Republic has created the SOF, or the Special Operations Forces, that seek to keep tabs on the Others, return to the Dome with Others and Losrians that have abilities that might be notably useful to the Republic, and manage resources in the Outlands.
But they are, themselves, Other. Many Others and Losrians are assigned a handler, to prevent them from rebelling, kept on a power-limiting, highly-addictive drug, and more or less kept as slave soldiers. And the poorest of humans gather far from the Dome's capital, finding food and shelter only in the barbaric gladiator games in the HoloArena. Sacrifices, the Republic says, must sometimes be made, for the greater good. Some must live in poverty and oppression, that others can live in wealth and prosperity.
Similarly, the remnants of the Andascan Federations' destroyed city-states, populated by Losrians, have banded together either with one of the new Outlander settlements, or another city-state. Losrians are the only race known to be able to tolerate crossing into a speckle, a location where dark magic thrives. Others that cross into speckles, even humans, tend to be driven into a frenzy.
The people of the Dome consider the Outlanders to be the greatest threat to the Dome ever known, second perhaps only to the Losrians and their Andasca. They grow up on stories of how horrible and uncivilised the Outlanders are, bloodthirsty barbarians with no regard for life -- how terrible one must be, anyway, to be able to survive in the Outlands. The Outlanders, on the other hand, believe the Dome full of senseless idiots, unable to think for themselves, sheeple being herded with minimal effort and little give a damn for anyone but themselves.
The Outlanders and the Dome may never get along, just as one is always either human or Other. But they don't have time for their petty squabbles and trivial disagreements.
They are coming.