The Apocalypse

The war between life (Yrelia) and death (Argoth). Literally sundering the world, splitting it into The Mortal Plane and The Underworld. The war was fought between the Gods and their Archangels and Argoth and his Demons. The war ended when Yrelia banished Argoth from The Mortal Plane which created The Underworld.

During this war, some elves betrayed their kin and sided with Ilmora, who corrupted their bodies with demonic energy. Creating the race we know as Drow today.