Narcissa Malfoy (née Black) was a pure-blood witch, the wife of the Death Eater Lucius Malfoy, and the mother of Draco Malfoy. Born into the aristocratic House of Black, she was a staunch believer in the importance of pure-blood supremacy. Though she was never an official, marked Death Eater, she was a supporter of Lord Voldemort during the First Wizarding War and Second Wizarding War. Her primary allegiance, however, was not to Voldemort but to her family. Narcissa's defining moment came during the Battle of Hogwarts, when her overwhelming love for her son led her to betray Lord Voldemort, an act of deception that was instrumental in Harry Potter's final victory.
Narcissa was the youngest of three daughters born to Cygnus and Druella Black (née Rosier), making her a scion of the ancient and wealthy House of Black. Her elder sisters were Bellatrix Lestrange (née Black) and Andromeda Tonks (née Black). She was raised to believe fervently in pure-blood superiority and to despise Muggle-borns, Muggles, and blood traitors. Her family disowned her sister Andromeda for marrying the Muggle-born wizard Ted Tonks. Narcissa was the first cousin of Sirius Black and Regulus Black.
Narcissa attended Hogwarts School of Witchcraft and Wizardry, where she was sorted into Slytherin House (Pottermore). It was at Hogwarts that she met her future husband, Lucius Malfoy, a fellow pure-blood from a similarly wealthy and influential family.
Sometime after graduating from Hogwarts, she married Lucius Malfoy and took his surname. In 1980, they had their only child, a son named Draco Malfoy. While her husband and sister Bellatrix were loyal Death Eaters serving Lord Voldemort, Narcissa never received the Dark Mark. She nonetheless supported her husband and Voldemort's cause. After Voldemort's first downfall, Lucius evaded imprisonment in Azkaban by claiming he had been acting under the Imperius Curse, allowing the family to maintain their position of influence and wealth within the wizarding community, residing at their ancestral home, Malfoy Manor.
After Voldemort's return, the Malfoys' standing in his inner circle was precarious. Lucius's failure to retrieve the prophecy from the Department of Mysteries resulted in his capture and imprisonment in Azkaban. In a punitive act, Voldemort tasked Draco with the seemingly impossible mission of killing Albus Dumbledore. Fearing for her son's life, Narcissa defied her sister Bellatrix's counsel and travelled to Spinner's End to plead with Severus Snape for help. There, she demonstrated the depth of her maternal devotion by persuading a reluctant Snape to make an Unbreakable Vow. Snape vowed to watch over Draco, protect him from harm, and to carry out the murder of Dumbledore himself should Draco fail. After the fall of the Ministry of Magic, Malfoy Manor was co-opted by Lord Voldemort as a headquarters for his Death Eaters, much to the family's humiliation. Narcissa was present when Harry Potter, Ron Weasley, and Hermione Granger were captured and brought to the manor. Though she confirmed Harry's identity, her primary concern was the fate of her son, who had been disarmed by Harry during the ensuing skirmish. During the final moments of the Battle of Hogwarts, Voldemort performed the Killing Curse on Harry in the Forbidden Forest. Wanting to confirm the kill without approaching himself, he ordered Narcissa to check if Harry was dead. Kneeling beside Harry's body, she quietly asked him if Draco was still alive in the castle. Upon Harry's whispered confirmation, Narcissa lied directly to the most powerful Dark Wizard of all time, declaring that Harry Potter was dead. Her lie, motivated solely by the desire to re-enter Hogwarts and find her son, gave Harry the crucial protection he needed to stage his final confrontation with Voldemort. The Malfoys were last seen during the battle, huddling together and not participating further, focused only on their own survival.
Due to Narcissa's pivotal role in aiding Harry's victory, the Malfoy family avoided incarceration in Azkaban following the Second Wizarding War. Their reputation, however, was left in tatters.
Narcissa is described as a tall, slim witch who would have been attractive if not for a disdainful expression that suggested she was smelling something unpleasant. She had long, pale blonde hair, a trait she passed on to her son, and blue eyes. Her complexion was very pale, matching the aristocratic and cold demeanor of the House of Black. Her personality was defined by arrogance, pride, and a deep-seated belief in pure-blood doctrine. She was cold, disdainful, and looked down upon those she considered inferior. However, her most powerful and defining trait was her fierce and unconditional love for her son, Draco. This love proved to be her ultimate motivation, overriding her fear of Lord Voldemort and her loyalty to the Death Eaters' cause. Unlike her sadistic sister, Bellatrix, Narcissa did not appear to take pleasure in cruelty, acting instead out of self-preservation and a ferocious instinct to protect her family.
As a witch from a powerful and ancient family, Narcissa was undoubtedly a competent and well-trained magic-user.