Voldemort
Also known as Lord Voldemort, the Dark Lord, and He-Who-Must-Be-Named, Voldemort rose to power in the 1970s with a faithful following of dark wizards called Death Eaters. During his reign of terror through the 1970s and 1980s, no one was safe from Voldemort's cruelty except for those at Hogwarts; Professor Dumbledore was the only wizard that Voldemort still feared. Voldemort was unexpectedly torn from power when he attempted to perform the Killing Curse ("Avada Kedavra") on the infant Harry Potter. When Lily Potter sacrificed herself to save her son, she created a protective shield over Harry and, not only was Voldemort unable to kill the child, he nearly destroyed himself in the process. For the next eleven years, Voldemort existed only as a wraith, waiting to regain his strength. With Professor Quirrell's help, Voldemort successfully infiltrates Hogwarts in his effort to find the Sorcerer's Stone (which produces the Elixir of Life that can restore him to full power). Unfortunately, Harry retrieves the Stone for before Voldemort can get it and, upon Professor Dumbledore's entrance, Voldemort escapes in spirit form and leaves Quirrell to die. In the book, Voldemort is characterized by his ambition, resourcefulness, manipulation of weaker minds, and determination to regain his former power. Significantly, however, he is also identified for his lack of knowledge about love, an emotion which provided Harry with his mother's protective shield.