the players have several parties that adventure on different parts of an unimportant penninsula. there are parts of the world that are much more developed so this would seem hardly the place for earth shattering events. (The planet is much larger than earth and most of the main continent is arrid-dirt wasteland, by the way.) anyhow, each of these parties uncover signs of trouble and great evil.... a string of kidnappings is the result of drow war on an elven kingdom, demons invade a kingdoms farmland. peasants rebel, death cult forms, "bandits" seize mines. well as it turns out a lesser goddess of death has plotted to overthrow the greater goddess of death... the past troubles have been the effects of her drawing in artifacts of power. She has uncovered teh annulus and restored it... she is using the regalia of evil, and other certain artifacts to enhance its power in order to destroy the other goddess.
the players have fought her minions and each party sets out to this one capital city where they know this lesser goddess is planning to use as her base of attack. by this point the players control multiple characters and meet in this capital city at the adventureres guild. at this point the city is seiged by the rebllion, disguised demons that werent routed by the pcs beforehand and the lesser goddess' own necromancers guild. Their goal is to destroy the other necromancers academy beneath the city and take the alst of the needed artefacts.
OK this is getting drawn out i iknow so ill make it shorter.
avatars of both goddesss duel as the pcs fight hordes of undead and the high priests and arch liches of each goddess...
the "lesser" goddess wins. her main servant attains either divine rank 1 or 0 and the now epic level pcs go off to battle him while other gods try to destroy this usurper goddess. This is the classic set up of good versus evil and it calls to mind lodoss wars etc. what happens then is not so common.
she casts a global death spell
this kills everyone on the planet!
almost all gods are immediately forgotten and destroyed
this sets off major deific contingencies.
gods of magic, divination, and revenge use a mortal mage of immense power (more powerful than elminster)
as their channel to destroy her followers. He and his apprentices had contingencies of resurrection (wish) and rose immediately after tehy were slain. before this wizard could reset his contigency he had to sacrifice himself to annihilate this megadeathgoddess.
a powerful nature goddess tehn creates a global temporil stasis that affects only intelligent creatures(elves goblins humans etc.) this alsts for almost 10k years this allwos the earth to heal itself and ruins all the past achievements of the intelligent races
the only people who survive this global death are the aprpentices and spelljammers who return during the stasis. the only place the spelljammers survive is the large city of thyrmeceir where there were enough spelljammers returned to sustain a population...
again thsi is all very complicated and i donteven know if anyone is still reading this but here is my main point.
this sets up my own campaign setting...
each settlement searches for answers and knowledge adn desperately clings to tomes and scrolls. There are monastaries built and orders devoted to knowledge so that tehse survivors can piece together what happened. elves call a council and exile temselves to live together
dawrves leave and build their redoubts... and all non human races find it hard to sustain populations and are eventually thinning out in numbers. divine magic is limited as are diinations etc. and there will be a difference between shamans and clerics, adepts and wizards, belief and true faith... superstitions and the truth. each settlement forsm its own sort of city state that resembles social structure of noble houses... except it isnt about being noble but who has the most lore or who ahs the best scavengers,wizards or assassins.
the questions are
what should I do about the apprentices.... i know they survive but should they be wizard kings or what... and how do i get rid of other liches that respawn because of their phylacteries... maybe there are lots of leftover liches... idk
if you have any questions or ideas let me know id be happy to go into more detail haha and unforunately i really can!