I'm a fan of apocalypses that happened for understandable reasons, but which were still really bad.
As an example, if I ever run 13A, I have custom Icons for a post-post-apocalypse, where the world is now beginning to "rise" again, but the nature and success of that return are in doubt. The Thirteenth Age is an age of dawn, but is it a golden one or soaked in blood?
The Eleventh Age did not view itself as a "golden" age, but for those who endured its end and the horrors that followed, it came to be seen as one. It was an age of strife, but also an age of achievement. The dragonborn of the northern continents subsumed—by both diplomacy and conquest—the entirety of the landmass accessible to them. However, their navy was significantly inferior to that of the humans from the southern continent, so there was a tense peace (or, more accurately, cold war until one side or the other could wrest clear advantage.) Then, seemingly the gods themselves intervened, and a massive typhoon swept through the Girdle Ocean, destroying much of the humans' fleet in mere days. Within a month, dragonborn soldiers were already making a beachhead. The humans, unwilling to accept their inevitable defeat, resorted to darker and darker means to preserve their freedom, until finally, in an act of colossal blood magic, they sacrificed over ten thousand slaves simultaneously in order to tear open a portal straight to Hell, from which the pact-bound armies of darkness could fight off the invaders.
Unfortunately, the pact was of course extremely manipulative, and protected ONLY humans, not any other race or creature. Whenever any human resisted, they were slaughtered (or worse...) as much as the invaders were. And as the demons so gleefully noted, you'd be surprised what you can live through.
In less than a year, the southern continent was completely lost, and by the next, the dragonborn empire was on the verge of total collapse. The Icons gathered together to do something. All of them, even the twisted and evil ones, because they all knew the entire world was at stake. The Lich King and Great Gold Wyrm proposed a radical solution, a spell that would combine all their powers and completely seal the world off from extraplanar entities and forces. Desperate, and each thinking this would eventually give them an opportunity for a better bargain later, they agreed, and the Lich King cast the spell himself, flaring out in the process and seemingly ending his existence.
But he had deceived them, because the Sun is also a planar influence! So the Golden Age fell, the Age of the Sun died as a whimper in the twilight, and the Dark Age, or the Age of Ice, followed in its wake. The world slowly froze, and the remaining Icons bickered and feuded and scraped for the last vestiges of heat and life and magic. A vicious stalemate no one could break, until the Great Gold Wyrm had had enough. The petty squabbles, and the shame of having helped cause such suffering, embittered him against the other Icons, and he felt forced to unilaterally act. As one of the architects of the spell, he was able to break it and take its phenomenal power into himself, becoming more powerful than any other Icon...and then he filled the World-Wound himself, body and soul. Now he fights to protect the world, and inspire heroes to help bring an age of light...but the spell's power will not last forever.
A new sun rises over a world pulled back from the brink, changed unimaginably by war and horror and darkness and bitter, bitter cold. Tombs and monuments dot the land, the last vestiges of those who did not survive the Dark Age. The Dragon Empire is long, long dead—but hushed whispers say the Courtesan is the Emperor's heir, and her loose trade league the seed of a second Empire. Her recent alliance with the newest holder of the Storm Captain mantle has done nothing to quell these rumors. But dark forces still lurk, and the Pale Lady in the shadows of grave and tomb may prove that the Lich King's gambit has not yet run its course....
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