Deathwing the Destroyer,[1] formerly known as Neltharion the Earth-Warder, was one of the five Dragon Aspects and leader of the black dragonflight. Thousands of years ago, Neltharion was empowered by the Titans with dominion over the earth and the deep places of Azeroth. However, driven mad by the Old Gods, he turned against the other Aspects during the War of the Ancients. Among both mortals and dragons his name became one whispered with a feeling of fear and contempt.

My blessing upon you will seem humble compared to those which have been bestowed upon the others: the managing of time, of life, of dreams and magic. I offer you the earth. The soil, the ground, the deep places. But know that the earth is the basis of all things. It is where we are rooted. Where you must come from, if you are to go to. Here is whence true strength comes. From deep places...within the world, and within oneself. - Blessing of the Black Aspect, given by Khaz'goroth

Neltharion was originally the mighty black wyrm chosen by the titanKhaz'goroth to be one of the five Dragon Aspects, with domain over the earth and the deep places of the world. He was chosen as the caretaker of the continents of Azeroth, and he used his power to forge mountains and rivers for the benefit of mortal races.[3] In peaceful times, Neltharion was renowned for his wisdom and power, and he became known as Neltharion the Earth-Warder, a great protector of the land. Malygos the Spell-Weaver, the Aspect of magic, was his closest friend.

Then came the madness that destroyed Neltharion's mind, changing him and his kind forever and leading to the creation of the powerful item known as the Dragon Soul, later the Demon Soul. The inner-voices of the Old Gods convinced him that he could have power beyond his imagination if he served them. The voices made him paranoid of even his own black dragonflight. Neltharion began to yearn for a world dominated by his black dragonflight — a world in which the other dragonflights ceased to exist and Ysera and Alexstrasza would be his petty slaves for mating.

The Old Gods convinced Neltharion to create the Dragon Soul. With the help of goblins, Neltharion created a simple golden disc made of his blood and forged in the goblins' cauldrons and anvils deep beneath the earth. Empowered by Neltharion's magic, the simple disc was magically shielded so that the other Dragon Aspectscould not see within it. There was an evil within the disc, some taint of the Old Gods, though what exactly it is not known.