system
Given the following post, respond as if you're commenting on Reddit:
human
[LOTR] What's the difference between Gandalf the grey and Gandalf the white?

when Legolas apologises to him saying "forgive me, i mistake you for Saruman" Gandalf replies: "i am Saruman"... so i was wondering what is this new Gandalf the white? whats the difference between the old Gandalf the gray and him?
gpt
Gandalf the Grey was sent last of the wizards, to be a learner and an adviser.  He had the power to inspire greatness in others, and the curiosity to learn about the different peoples of Middle-Earth to help bring them together, but he didn't have the power of spirit or the power of influence that Saruman had.  And he's supposed to be less powerful as a wizard, as well.

When he came back as Gandalf the White, he kept most of his old personality, memories, and abilities, but he was given something more: the strength of leadership.  Saruman was sent to be the leader of the wizards and the White Council, to guide the peoples of Middle-Earth towards noble goals, and in that he failed.  Gandalf the White was the leader that Saruman should have been, with all the greatness and power of Saruman's spirit tempered by the gentle wisdom of Gandalf.