Abyssborn

The Abyssborn are Fiends who were never mortal, but instead were spawned directly from the substance of The Abyss. While Devils tend to be created from excarnate mortal souls, albeit stripped of their form and identity by death and immersion in the waters of the Styx, many Demons are Abyssborn.
In usage, however, the term is typically not used of any but the most powerful of their kind, such as the mighty Ixis Gloomshrouded, whose gargantuan bones form the steps of the Fathomless Vertex, and Rael-karn the first Demon King of the Crawling Caverns.