The Maiar were primordial spirits created to help the Valar first shape the World. They were numerous, though not many were named. Their chiefs were Eönwë, banner-bearer and herald of Manwë, and Ilmarë, the handmaid of Varda.
Five of these spirits, in the Third Age, became the incarnated Wizards.
Each of the Maiar was associated with one or more particular Vala, and was of similar stock, though less powerful. For example, Ossë and Uinen, as spirits of the sea, belonged to Ulmo the Sea-king, while Curumo (known in Middle-earth as Saruman) belonged to Aulë the Smith. Others included Mairon (originally also of Aulë, known in Middle-earth as Sauron), Aiwendil (known in Middle-earth as Radagast), who belonged to Yavanna the Fruit-giver, and Olórin (known by the Elves as Mithrandir but came to Middle-Earth as Gandalf) who belonged to Manwë the Wind-king and Varda the Star-Queen. Gandalf's ways took him often to the house of Nienna the Weeper, and from her, he learned pity and patience, which perhaps aided him in his later struggles to unite the Free People of Middle-earth against the power of Sauron.
Alatar and Pallando, later known as the Blue Wizards, traveled to the East, never returning to the West; their fate is unknown. The Balrogs (Valaraukar in Quenya) were corrupted Maiar who became Melkor's most trusted and terrible servants. Melian served both Vána and Estë.
The Sun and Moon were also piloted by Maiar: Arien, a spirit of fire uncorrupted by Melkor, was chosen for her radiant beauty and fierce devotion to the workings of the Valar, was selected to guide the Sun, while Tilion, a hunter in the company of Oromë, was chosen to steer the Moon.
