Not much is known of the Dagda Mor's background, other than that he was an Elven druid in the days before the Age of Man who was corrupted by the Ildatch, an artifact of immense dark power. He became so powerful that he was able to unite the demonic hordes in an attempt to destroy the ancient elves and conquer the world. He was defeated when the elves created the Ellcrys; sealing him and the thousands of demons that followed him, into an alternate dimension known as the Forbidding.