Mairon (Sauron) in his forge

Sauron's original name was Mairon. He was the mightiest Maia of the Vala Aulë the Smith, and learned much from Aulë of smithing and handiwork, becoming a great craftsman and "mighty in the lore of" Aulë's people. He was among the most powerful Maiar.

In the Days before days, Mairon was as Eru had created him: good and uncorrupted. His greatest virtue was his love of order and perfection, and dislike of anything wasteful. However, this would also prove to be the cause of his downfall, as Mairon saw in Melkor the will and power that would help him achieve his personal ends quicker than if he pursued them alone. However, while Melkor wanted to either control or destroy Middle-earth itself, Mairon's desire was to dominate the minds and wills of its creatures for what he perceived to be their own benefit. To see his marvelous designs through, Mairon sought to increase his innate power and this power in time became the end in itself; so he joined with Melkor, soon becoming his chief agent.