The creator of the fictional world in J.R.R. Tolkien’s legendarium is Eru Ilúvatar.
Eru Ilúvatar is the supreme being in Tolkien’s mythology and the source of the Ainur, powerful spirits who participate in the Music of the Ainur. The music becomes the pattern for the creation of Eä, the universe in which Arda, the world of the stories, exists.
The name is sometimes confused with Manwë, Morgoth, or Aulë. Manwë is the chief of the Valar, Morgoth is the first Dark Lord, and Aulë is the Vala associated with craftsmanship and the creation of the Dwarves. Eru stands above these beings. His role is presented most directly in the opening material of The Silmarillion, especially “Ainulindalë,” which explains creation through mythic music rather than through a conventional chronological narrative.