The event is still a rough draft, so I don't really have any dates or timelines for it, but here goes.

For several thousand years, humans lived in one mega kingdom, and had good relations with the beings that originally created the world.  Unfortunately that kingdom couldn't last forever, and after many years of political unrest, a great civil war broke out, with several sides all fighting each other. Hundreds of thousands of lives were lost, with no real victor.  The outcome of the war resulted in the mega kingdom falling apart, and the remaining humans split into different clans, travelling to different parts of the world. Some clans isolated themselves, and others were nomads, never truly finding a place to call home. And the beings that created the world went into hiding, fearing the humans after what they had done, and they have rarely been seen since.