Khamûl was one of the nine Ringwraiths, second only to the Witch-king himself. He was called Sauron's lieutenant, Shadow of the East, and the Black Easterling. He was a lord of Easterlings before being given one of the Nine Rings. He was the only Ringwraith whose name was given by Tolkien.
Khamûl was the Wraith who pursued the Hobbits to the Ferry at Buckleberry in the Shire, and who asked Hamfast Gamgee for "Baggins" just before Frodo Baggins left Hobbiton. He commanded the fortress of Dol Guldur after Sauron's return to Mordor. Following the destruction of the One Ring, Khamûl perished with the rest of the Ringwraiths.