For this ranking, “dark wizard” refers broadly to characters who practiced the Dark Arts or spent a significant part of their lives aligned with them. From Voldemort's most fanatical followers to the Dark Lord himself, these are the most powerful dark witches and wizards in the Harry Potter movies. 7 Peter PettigrewPeter Pettigrew in Harry Potter looking scared with a wand pointed at his wrist. 1 Lord VoldemortClose Ralph Fiennes as Lord Voldemort holding a wand in Harry Potter and the Order of the PhoenixTom Riddle writing I am Lord Voldemort in Harry Potter and the Chamber of SecretsLord Voldemort in Harry Potter and the Deathly Hallows Part 2There was never much suspense surrounding the top spot. Even so, when it comes purely to the Dark Arts, nobody else in the eight Harry Potter movies comes particularly close.