The Maiar are a class of beings from J. R. R. Tolkien's high fantasylegendarium. Supernatural and angelic, they are "lesser Ainur" who entered the cosmos of Eäin the beginning of time. The name Maiar is in the Quenya tongue from the Elvish root maya- "excellent, admirable". Commentators have noted that since the Maiar are immortals but can choose to incarnate fully in Men's bodies on Middle-earth, they can be killed; Tolkien did not explain what happened to them then. Others have observed that their semi-divine nature and the fact that they can be sent on missions to work out the divine purpose makes them much like the angels of Christianity.
Tolkien stated that "Maia is the name of the Kin of the Valar, but especially of those of lesser power than the 9 great rulers". In the Valaquenta, Tolkien wrote that the Maiar are "spirits whose being also began before the world, of the same order as the Valar but of less degree". In the Valaquenta, it is also written that many Maiar associated themselves with a Vala; for example, Ossë and Uinen, who ruled the Seas, acted under Ulmo, while Curumo, who came to be known in Middle-earth as Saruman, was with Aulë. Sauron also was with Aulë the smith, before being corrupted by Melkor. Sauron continued his association with smithcraft by making friends with the Elven-smiths of Eregion, so that he could gain power over the other rings by forging his One Ring. Being of divine origin and possessing great power, the Maiar can wander the world unseen or shape themselves in fashion of Elves or other creatures; these "veils", called fanar in Quenya, could be destroyed, but their true-being could not. Rarely did the Maiar adopt their visible forms to Elves and Men, and for that reason, very few of the Maiar have names in their tongues, and the elves do not know how many of the Maiar exist.
Named Maiar
There were numerous Maiar, but only some are named. The Maia Eönwë is the Herald of Manwë. He led the hosts of the West in the War of Wrath in which Morgoth was finally overthrown and Thangorodrim destroyed. Melkor, the evil Vala, corrupted many Maiar into his service. These included Sauron, the main antagonist of The Lord of the Rings, and the Balrogs, his demons of flame and shadow. These are called in Quenya Úmaiar. Melian was a Maia who went to Middle-earth before the First Age, where she fell in love with the Elven-king Elu Thingol, King Greymantle, and with him ruled the kingdom of Doriath. When war with Morgoth came to Doriath, she used her powers to guard and defend it with a protection called the Girdle of Melian. She had a child with Thingol, a daughter named Lúthien, said to be the fairest and most beautiful of all the Children of Ilúvatar. The scholar of English literature Marjorie Burns describes Melian as "the most traditional enchantress in Tolkien's literature", comparing her Celtic nature to that of the elf-queen Galadriel.
Wizards
In about, the Valar sent several Maiar to Middle-earth to help contest the evil of Sauron. They had great skills of hand and mind but were cloaked in the guise of men, seemingly old but of great vigour. Their mission was to guide elves and men by gaining trust and spreading knowledge, not by ruling them with fear and force. They were known as the Istari or Wizards, and included Gandalf the Grey, Saruman the White, Radagast the Brown, and two Blue Wizards who are mentioned in passing but do not appear in Tolkien's narratives.
Balrogs
The Balrogs were fire-demons of great power, serving first the Vala Morgoth and then his successor the Maia Sauron in Middle-earth. They were large and physically strong, armed with fiery whips, and were among these Dark Lords' most dangerous servants. They are more powerful even than dragons.
Interpretation
The theologian Ralph C. Wood describes the Valar and Maiar as being what Christians "would call angels", intermediaries between the creator, named as Eru Ilúvatar in the Silmarillion, and the created cosmos. Like angels, they have free will and can therefore rebel against him. Grant C. Sterling, writing in Mythlore, states that the Maiar resemble the Valar in being unable to die, but differ in being able to choose to incarnate fully in forms such as men's bodies. This means that, like Gandalf and the Balrogs, they can be killed. He notes that Sauron's inability ever to take bodily form again after his defeat could be the result of having given his power to the One Ring, but that the fate of killed Maiar remains unclear. Jonathan Evans, writing in the J.R.R. Tolkien Encyclopedia, calls the Maiar semidivine spirits, and notes that each one is linked with one of the Valar. He states that they have "perpetual importance in the cosmic order", noting the statement in the Silmarillion that their joy "is as an air that they breathe in all their days, whose thought flows in a tide untroubled from the heights to the deeps." Evans notes, too, that Arien and Tilion are central in Tolkien's myth of the Sun and Moon.