Eru Ilúvatar is J.R.R. Tolkien’s supreme creator deity in The Silmarillion.
In Tolkien’s mythology, Eru brings the Ainur into existence and gives them the initial musical theme from which the great Music of the Ainur develops. The world, called Arda, is created through this music and its unfolding. Eru therefore stands above the Valar and all other beings in the legendarium.
The name combines two titles: Eru means “The One,” while Ilúvatar means “Father of All.” The Ainur include the Valar and Maiar, powerful spiritual beings who enter the created world. Melkor, later called Morgoth, is the greatest of the rebellious Ainur and becomes the main enemy of the First Age.
Eru is sometimes confused with Manwë or Morgoth because both are central to the early history of Arda. Manwë is the chief of the Valar, while Morgoth is a fallen Ainur; neither is the creator deity.