Saruman

Saruman the White was an Istar or wizard who lived in Middle-Earth. He was the head of the White Council in his time and lived in Orthanc. He is also known as Curunir or Curomo. He studied the arts of the enemy in depth and found there great promise of wealth and power. So drawn was he to the Enemy that he studied that he was corrupted, and sought to become a great Power himself.

He fashioned his fortress Orthanc in mimicry of the great Barad-Dur, Dark Tower of Mordor, and built up his strength by taking Orcs and Easterlings into his service. He developed through his own arts a new breed of Orc, the fighting Uruk-Hai, which unlike most other Orcs could withstand the sunlight, and did not feel pain or fear. These were the Orcs that pursued the Fellowship of the Ring along the length of Anduin, and finally captured Merry and Pippin, two members of the Company.

He was thrown out of the White Council by the reborn Gandalf the White, who came to Isengard after a great battle between Saruman and Theoden, king of Rohan. He lost much of his former power, and his staff was broken. He refused to forget his plots and help Gandalf reshape Middle-Earth, however, and went to the Shire to continue his evil deeds. He pillaged and scoured the Shire, seeking perhaps to turn it into a stronghold such as he had at Orthanc. But eventually, he and those in his employ were defeated by the hobbits of the Shire themselves, rising up against their oppression. He was finally killed by his own servant "Wormtongue" Grima son of Galmod who slit Saruman's throat, and he came to Middle-Earth never again.