The “Ore Rinna” is an old dwarven legend about Deothar, Elder God of Creation who the first metal. A pure ore known as the Prima Materia (Ore Rinna in Dwarvish), so strong it could only be forged by Deothar himself. It is said that this ore was used to create Orrin and resides within the center of the planet.
The Legend of Ore Rinna (Translated from Dwarven):
In the beginning the great god Deothar swallowed ancient debris and formed the first metal, Prima Materia within his fiery stomach. With his mighty hammer, Mjolnir he forged out the land, tempered the skies and quenched it all with the sea. Within the heart of Orrin lies the Prima Materia, awaiting those worthy of forging it again.