What kind of being is Sauron in Tolkien’s legendarium? The answer is Maia.
Sauron is a Maia, an immortal spiritual being who existed before the shaping of the physical world. He was originally called Mairon and was associated with Aulë, the Vala of craftsmanship and smithing. Sauron’s gifts for order, making, and organization later became instruments of domination.
He was corrupted by Melkor, later known as Morgoth, and became one of Morgoth’s most powerful servants. After Morgoth’s defeat at the end of the First Age, Sauron continued the pursuit of absolute control. In the Second Age, he deceived the Elves of Eregion, helped create the Rings of Power, and secretly forged the One Ring in the fires of Mount Doom.
A common mistake is calling Sauron a Vala because he is vastly more powerful than ordinary beings. The Valar are the greater order of divine spirits, while Maiar are lesser but still immensely powerful spirits. Sauron is also not an Elf or a Dúnadan; his ability to assume attractive forms, including Annatar, reflects his spiritual nature and skill at deception.