Lord Voldemort

Lord Voldemort is the arch-villain of the Harry Potter books. He is so feared by magical people that they refer to him as "You-Know-Who" or "He-Who Must-Not-Be-Named" rather than saying his name out loud.

Voldemort murdered Harry's parents when he was a baby, but Harry's mother Lily died trying to defend him. This act of loving sacrifice served as life-long protection for Harry. Nonetheless, Harry got a lightning-shaped scar on his forehead when Voldemort tried to curse him.

It is possible to break the name Voldemort into the French phrase "vol de mort" which has multiple translations. The most commonly cited is "flight of death", but other meanings include "flight from death" and "theft of a dead body." Voldemort's followers are called death eaters, and they are hiding from the Ministry of Magic. Voldemort himself fled when he couldn't kill Harry.

SPOILER ALERT!! Read no further to avoid spoilers!

Voldemort is confronted by Harry three times in the first four books. He takes up residence under the turban of the nervous Defense Against the Dark Arts master in year one, but he can't touch Harry and is defeated. As Tom Riddle, he lures Ron Weasley's younger sister, Ginny, into using dark magic to turn a cat and some people into statues but is defeated when Harry's loyalty inspires Fawkes, a phoenix, to provide him a sword in the nick of time (see Chamber of Secrets). In his scariest confrontation with Harry Potter yet, Voldemort reanimates a body and attempts to kill Harry with magic in front of his reassembled Death Eater followers, but Harry's wand is linked and undoes Voldemort's spells.

Voldemort's real name is Tom Marvolo Riddle; in the second book he explains that Voldemort is derived from an anagram of his name:

Tom Marvolo Riddle = I am Lord Voldemort

In the French version of Harry Potter and the Chamber of Secrets, Voldemort's true name is changed to Tom Elvis Jedusor to accomodate the anagram:

Tom Elvis Jedusor = Je suis Voldemort