Chronicles of Neverael
The Sidhe, much like any other culture or civilization which lasts for a long enough time, eventually grew toward a state of obscene decadence – where amusement and self-gratification became the only reasons to do anything and life was taken for granted. Amidst this decadence, a minor cult arose amongst the upper echelons of society which made contact with…something. This dark entity or entities had been feeding off of the corruption being generated by the Sidhe people in the Astral Miasma and had acquired a terrible purpose toward which it manipulated its newfound worshipers.
Using forbidden sorcery and a form of hybrid magick taught to them by the dark entity in question, this cult (called the Fomoraei) ripped open a rift into the heart of the corruption festering in the Astral Miasma and allowed it to flow out into physical reality – killing one quarter of their race instantly, blasting and tainting the landscape for hundreds of miles, and releasing a vast array of demons into the world.
The event came to be called Rending Night. Rending Night sparked a continent-wide civil war fought between the Heldyr (a faction who wished to clean up Sidhe society and return it to its noble roots and glory days) and the Fomoraei (growing rapidly in number after their awful display of power). This war, the Heldyr-Fomoraei War, would last over a millennium and drive those Sidhe not affiliated with the Fomoraei to the brink of extinction.