Imagine a world where the good races are oppressed by two controlling pantheons. Orcus and Lloth had united 300 years ago to overthrow the world ruled by Corellon Larenthian and Rhianan of the Elves, Moradin and Clangedin Silverbeard of the Dwarves. The humans had only minor gods at the time.. Halflings and Gnomes were again minor races and they had their own influences but they tended to be secluded from the rest of the world.
As the story has been told over the years, a great war occurred lead by the gods of the orcs and the drow. Lloth made a pact with Orcus to overthrow Correlon. Lloth is the banished daughter of Correlon. Lloth was invited by her father Correlon to a parlay as she wanted to be forgiven for her past transgretions against her father. Correlon was skeptical but he agreed to the meeting
Lloth deceived Correlon and slipped him a powerful tonic which waned his influence on the prime material plane. The tonic impeded his ability to grant powers to his higher level clerics. Correlon’s avatars were still able to grant up to 3rd level spells but nothing higher could be prayed for. The clerics of Corellon lost faith and the high priestess made a deal with Lloth that if she was granted the power she had lost from Corellon she would influence the other elven clerics to convert or they would die. The priestess ended up killing her entire clergy within the main elven imperial city known as Cantatta.
On the second front, Orcus gathered the entire force of the orcan army to come together under one banner. The Clawfoot tribe rose up first against the dwarven strongholds and underground citadels. With the long reigning peace created by good factions except for minor skirmishes the dwarven armies were unprepared for the humanoid onslaught. Even the well trained dwarven defenders were no match for the humanoid armies. Moradin and Clangedin Silverbeard were also caught off guard as Orcus brought together all the humanoid pantheons to strike at once. The upheaval on the other planes was quick forcing Moradin and Clangedin into a corner and they fled. The dwarves stood their ground but were forced to go deeper into the mountains and retreat. The surface dwarves tried to align themselves with the elves in defeating the armies of Clawfoot through magic rather than divine forces. Magic users from the elves were no match to the combined magical and divine forces from Lloth and Orcus.
The elves tried to retreat but in a unexpected maneuver the newly converted high priestess cursed and slaughtered all of the elders and any adult elf in order to remove any possible ties with Correlon and the old elven pantheon. The extinction of the elven culture, arcana and religion was at hand all in one swoop.
The Age of the Obsidian Order had begone. Every other race that remained was put into slavery or if deemed worthy just second class citizens of the new empire.
Any tie to the old world was systematically desecrated, and destroyed. The elves that did manage to survive formed into scattered tribes and eventually worshipped nature. The tribes focused around animals such as the wolf or the bear.
The humans were scattered but they were able to adapt more quickly to their environment and their settlements were still small and posed no threat to the orcan army.
Magic used by the good races is almost non existent. There are only rumours about old temples or places in which treasure may be found.
Religion is outlawed except for the worship of Lloth or the humanoid pantheons.
Your world is in turmoil…maybe it will be you who breaks free and creates something epic.