J.R.R. Tolkien’s fictional creator deity in The Silmarillion is Eru Ilúvatar.
Eru Ilúvatar, whose name means ‘The One, Father of All,’ stands at the beginning of Tolkien’s mythology. In the creation account, he brings the Ainur into being and gives existence to the world of Eä.
The Ainulindalë, or Music of the Ainur, describes how the world’s design emerges through music. Melkor, the most powerful of the Ainur, introduces discord, but Ilúvatar incorporates that discord into a larger design.
Eru is often confused with powerful beings such as Manwë, Melkor, or Aulë. Those figures are Ainur within the created order, whereas Eru is its supreme creator.