Saruman

Saruman the White is a fictional character and a major antagonist in J. R. R. Tolkien's fantasy novel The Lord of the Rings. He is leader of the Istari, wizards sent to Middle-earth in human form by the godlike Valar to challenge Sauron, the main antagonist of the novel, but eventually he desires Sauron's power for himself and tries to take over Middle-earth by force. His schemes feature prominently in the second volume, The Two Towers, and at the end of the third volume, The Return of the King. His earlier history is given briefly in the posthumously published The Silmarillion and Unfinished Tales.

https://en.wikipedia.org/wiki/Saruman