The great smith and craftsman of the Valar, master of all the substances of which Arda is made, and spouse of Yavanna Kementari. Aule delights above all in the labour of making and in the understanding of materials, and much of the fabric of the earth -- its metals and gems and the bones of the mountains -- is of his ordering. He is akin to Melkor in the love of craft; yet where Melkor grew jealous and possessive of his works and desired to be their lord, Aule is humble, taking joy in the making itself and offering his works freely to the will of Iluvatar.
So great was his eagerness for the coming of the Children that Aule made the Seven Fathers of the Dwarves in secret, deep beneath the mountains, before the appointed time. When Iluvatar rebuked him, Aule in sorrow raised his hammer to destroy them -- and the One, seeing that his humility was true and not feigned, took pity and gave the Dwarves life and will of their own, bidding them sleep until the Firstborn should awaken. Aule was the teacher of the Noldor in their smithcraft, and Feanor and Celebrimbor came of his tutelage; but his greatest pupil among the Maiar was Mairon, afterward called Sauron, who turned the gifts of his master to evil when Melkor seduced him.