The Maiar (Quenya Tengwar: full spelling tlE`C6 or vowel-abbreviated spelling tl`6; IPA: [ˈmaɪ.ar] or Third Age Middle-earth [ˈmaɪjar]) (singular Maia; tlE`C or tl`) were those spirits which descended to Arda to help the Valar shape the World. They were supposed to be numerous, yet not many were named. Their chiefs were Eönwë, banner-bearer and herald of Manwë, and Ilmarë, the handmaid of Varda.Each of the Maiar was associated with one or more particular Vala, and were of similar stock, though less powerful. For example, Ossë and Uinen, as spirits of the sea, belonged to Ulmo, while Curumo (Cunneir), who came to be known in Middle-earth as Saruman, belonged to Aulë the Smith. Others included Sauron (originally also of Aulë's people), Aiwendil, who was known in Middle-earth as Radagast the Brown and belonged to Yavanna, and Olórin, (known by Elves as Mithrandir and by Men of the West as Gandalf), who belonged to Manwë and Varda. Gandalf's ways took him often to the house of Nienna, and of her he learned pity and patience, which perhaps aided him in his later struggles to unite the Free Peoples of Middle-earth against the power of Sauron.
Alatar and Pallando, known as the Blue Wizards, travelled to the East, and never returned to the West; their fate is unknown, though Tolkien wrote that they had probably also failed in their mission, but established cults in the East. The Balrogs, like Sauron, were Maiar corrupted by Melkor, also known as Morgoth. Their associated Vala is not known. Melian served both Vána and Estë.
The most powerful of the Maiar such as Eonwe or Sauron and possibly others, were powerful enough to oppose a Valar. One such example was Ungoliant, After she devoured the gems of the noldor she grew to great size and managed to overcome Melkor after draining his power and webbing him into a cage, forceing him to scream for help from the Balrogs.