The grey wizard in J.R.R. Tolkien’s The Lord of the Rings is Gandalf.
Gandalf first appears in The Hobbit as a wandering wizard who arranges Bilbo Baggins’s participation in the quest against Smaug. In The Lord of the Rings, he becomes a central guide in the struggle against Sauron and helps unite the Free Peoples of Middle-earth.
His title changes after his confrontation with the Balrog in Moria. When he returns, he is known as Gandalf the White, replacing Saruman as the chief of the Istari in the story’s symbolic order. This transformation is sometimes confused with a change of identity, but Gandalf remains the same character.
Tolkien based the wizard’s visual impression partly on an illustration of a postcard figure labeled “Der Berggeist,” or “The Mountain Spirit.” Gandalf’s role combines wisdom, humor, authority, and moral encouragement rather than simple magical power.