"I am Deathwing. The Destroyer. The end of all things. Inevitable. Indominatable. I am the CATACLYSM!"
Deathwing (formerly known as Neltharion) was the original Aspect of Earth, but became the "Destroyer" and brought about the Cataclysm that nearly tore Azeroth apart.
After using the Twilight's Hammer Clan to attempt to destroy the lesser races, Deathwing worked towards accomplishing what he called the "Hour of Twilight" through using Black, Twilight, and Chromatic Dragonflights to destroy mortal races. Deathwing was slain when he was eventually countered by the Aspects and Thrall, who used an augmented Dragon Soul to wound him.