lord voldemort (born tom marvolo riddle) is a fictional character and the main antagonist in the harry potter series of children's books. the books were written by j.k. rowling. voldemort first appears in the 1997 fantasy novel "harry potter and the philosopher's stone". in the "harry potter" movies, voldemort is played by actors richard bremmer, christian coulson, ralph fiennes, hero-fiennes tiffin, and frank dillane.