"With the Valar came other spirits whose being also began before the World, of the same order as the Valar but of less degree. These are the Maiar, the people of the Valar, and their servants and helpers."
The Maiar were other spirits that helped the Valar in their creation of the world. Each of them was associated with a particular Valar, and often had qualities from them. Sauron was student of Aule the Smith, but later followed Morgoth. Saruman was also a student of Aule. Radagast was a follower of Yavanna the Fruit-Giver, and Gandalf was a follower of Manwe the Wind-King. Other Maiar include the Blue Wizards and the Balrogs who were corrupted by Morgoth.