Gandalf is one one the five Istari sent to Middle-earth by Valar. He’s Maia and his original name was Olórin.
Tolkien once described Gandalf as an angel incarnate; later, both he and other scholars likened Gandalf to the Norse god Odin in his “Wanderer” guise.
He was known as Gandalf the Grey until his fall in the mines of Moria; when defeating the Balrog, the Flame of Udûn, the darkness took him but he was brought back to fight Sauron as Gandalf the White.
