Bellatrix Lestrange (née Black) is the first female Death Eater introduced in the books, and one of the most faithful members of Voldemort's inner circle. She is described as being highly attractive yet gaunt due to Azkaban and described with long, straight black hair and dark heavily lidded eyes. Bellatrix is often portrayed as looking slightly crazy and, more than once, it is implied that she is paranoid, mentally unstable, beautiful and fanatically devoted to Voldemort. Despite her apparent mental instability, she is a witch of prodigious ability, as demonstrated by all her victories in duels against other characters, and as noted by Harry in the final book.
Bellatrix was born to Cygnus Black and Druella Rosier and has two sisters, Andromeda and Narcissa. She is also a first cousin to Sirius and Regulus Black, and an aunt to Draco Malfoy and Nymphadora Tonks. Bellatrix married Rodolphus Lestrange two years after leaving Hogwarts "because it was expected of her" to marry a pure-blood. However, Rowling stated in an interview that Bellatrix truly loved Voldemort.[4] In Harry Potter and the Goblet of Fire, Rowling uses Dumbledore's Pensieve as a plot device to reveal that Bellatrix, rather than deserting Voldemort after his downfall like many other Death Eaters, is part of the group of dark wizards – along with Barty Crouch Jr, Rodolphus and Rabastan Lestrange – that torture well-known Aurors Frank and Alice Longbottom in an attempt to gain information about Voldemort's location. For using the Unforgivable Cruciatus Curse to torture the Longbottoms until they go insane, Bellatrix and her three associates are sentenced to life imprisonment in Azkaban.
Fourteen years after Voldemort's fall, Bellatrix is one of the many Death Eaters who escaped Azkaban and rejoined him. She is present at the battle of the Department of Mysteries in the climax of Harry Potter and the Order of the Phoenix, in which a group of Death Eaters attempt to steal Sybill Trelawney's prophecy pertaining to Voldemort's downfall. Rowling let Bellatrix prove her magical powers during the mission when she overpowers her niece Tonks and Kingsley Shacklebolt in one-on-one duels, kills her cousin Sirius by blasting him through the veil in the Death Chamber, and deflects one of Dumbledore's spells as she makes her escape. Harry attempts to use the Cruciatus Curse on her in revenge for killing Sirius, but the curse is ineffective due to the lack of real cruelty behind it. Before she can do any more, Bellatrix is subdued by Dumbledore in the Ministry of Magic's Atrium while he duels Voldemort. Voldemort intercedes on Bellatrix's behalf, grabbing her and taking her with him as he Disapparates, though not before being glimpsed by Ministry officials