Lord Voldemort is a fictional character and the main antagonist in the Harry Potter novel series written by British author J. K. Rowling. Voldemort first appeared in Harry Potter and the Philosopher's Stone, which was released in 1997. Voldemort appeared either in person or in flashbacks in each book in the series, except the third, Harry Potter and the Prisoner of Azkaban, where he was only mentioned. Voldemort has also appeared in all the corresponding film adaptations as of present date, except the third. Voldemort has been voted number one in polls for both literary and film villains. In the series, Voldemort is the archenemy of Harry Potter, who according to a prophecy has the power to defeat him. He aims to conquer not just the Wizarding world, but the Muggle (non-magical) world as well. He is so feared that almost no one uses his real name, instead referring to him as "You-Know-Who" or "He-Who-Must-Not-Be-Named." Even his followers only refer to him as the "Dark Lord". He was born Tom Marvolo Riddle, the last descendant of wizard Salazar Slytherin, one of the four founders of Hogwarts School of Witchcraft and Wizardry.