She is the daughter of Ted Tonks and Andromeda Black, cousin to Sirius Black, and sister of Narcissa Black and Bellatrix Black. Nymphadora herself is aunt to Draco Malfoy, the son of Narcissa and Lucius Malfoy.
During the final scenes of Harry Potter and the Order of the Phoenix, Tonks accompanies Alastor Moody, Sirius Black, Remus Lupin, and Kingsley Shacklebolt in fighting the Death Eaters though she becomes injured in the process and falls unconscious. Moody tries to revive her but she remains unconscious and is taken to St. Mungo's Hospital after the fight with Lord Voldemort. She then returns in the final pages of the book along with Alastor Moody, Remus Lupin and some of the Weasley's to confront Vernon Dursley, Petunia Dursley and Dudley Dursley about not giving Harry a hard time when he is at their house, Number Four Privet Drive.