From Dragon Eye Atlas
The ancient elves and - presumably - other ancient races walked with the gods. A rich pantheon of both good and evil deities covered every aspect of the world.
Then, war broke out in the heavens. An ancient god had been awoken, from a time before time. The Nameless One as he is called in myths as even his name is not remembered by elves nor dwarves (nor any of the younger races, of course) had been sleeping or locked away for ages. When he awoke, he found the world not as he was used to it, and people of all races praying to new gods.
His desire to return to his previous power sparked a war among gods and their followers - both mortal and supernatural. The skies were ablaze with magic energies, angels and demons joined battle as did the gods themselves.
In the end, the world was smashed apart in a cataclysm of magic that ended the gods, or their presence. Many gods fell and were destroyed, others no longer walk among the mortal races.
Since those days, those of the gods that remain have kept to themselves, speaking through prophets and acting through miracles. Whether this was by choice, by a kind of divine treaty, or because they no longer can do so is hotly (though cautiously for not angering any gods) discussed among those interested in arcane topics.
The Gods Wars are part of the Epoch of Destruction.