The Ainur are the spirits who existed with Ilúvatar, and helped him to create the world Arda through the Music of the Ainur. After the creation of Arda, many of the Ainur worked to guide and order its growth. Of these there were fifteen more powerful than the rest. Fourteen became the Valar. The fifteenth, Melkor, became the first Dark Lord. The lesser Ainur that accompanied the Valar into Arda are known as the Maiar.