According to a dark prophecy a Maia will descend from Heavens to aid Morgoth in breaking free from the Doors of Night . He supposedly will be a Demon of the Void equal to Sauron. A powerful being, he sets forth during the last days of evil in the battle known as the Third Song or Dagor Dagorath. He was believed to have once been the chief Mandos folk,who had left his master before his descent down to Arda.