Bellatrix Lestrange was born Bellatrix Black, first cousin to Sirius Black, and sister to Narcissa Black and Andromidia Black. Narcissa is mother to Draco Malfoy and Andromeda to Nymphadora Tonks.

Bellatrix became a Death Eater and married Rodolphus Lestrange, brother of Rabastan Lestrange. By that time, she had become a sadist. The three of them and Barty Crouch Jr used the Cruciatus Curse on Neville Longbottom's parents until they went insane. For that crime they were judged and sent to Azkaban. Fourteen years later, the three of them were amongst the imprisoned Death Eaters who broke out and rejoined Lord Voldemort. The Lestranges are considered some of Voldemort's most devoted followers.

She was in a group of Death Eaters who tried to steal a prophecy belonging to the Department of Mysteries in the Ministry of Magic from Harry Potter. She also murdered Sirius Black in a duel at the Ministry. She escaped from the Ministry with Lord Voldemort, and is presumably now with him at the end of Harry Potter and the Order of the Phoenix.