Sauron

Sauron is known through old tales before he ever appears: he is the Dark Lord, maker of the One Ring, the Enemy whose shadow lies over Middle-earth. In an earlier age he forged a master ring in secret to rule the Rings of Power, and he was overthrown in a great war of Elves and Men, when Isildur cut the Ring from his hand. Now, word comes to the Shire that Sauron has arisen again. He has returned to Mordor, his dark land in the east, where the Dark Tower is rebuilt and his servants gather. Chief among the fears Gandalf brings to Bag End is this: the Enemy lacks only the One Ring to complete his power, and he is seeking it. The Black Riders abroad on the roads are his most terrible servants, sent out to hunt for it.