A villain from the Harry Potter series of books by J.K. Rowling. Often referred to as "He-Who-Must-Not-Be-Named" and "You-Know-Who."
Lord Voldemort led a group of Dark Wizards known as the "Death Eaters." Voldemort and his Death Eaters were only stopped after a failed attempt to kill Harry Potter. Lord Voldemort lost his body (as well as his magical abilities) in the attempt, leaving Harry Potter with nothing more than a lightning shaped scar on the boy's forehead.
After Voldemort's disappearance many of his followers were killed or imprisoned at Azkaban while others escaped and awaited Lord Voldemort's return to power.