Professor Dolores Jane Umbridge is the central antagonist of the 2003 book Harry Potter and the Order of the Phoenix and its 2007 film adaption of the same name. She was a Ministry of Magic official and served as Senior Undersecretary to the Minister for Magic under three successive ministers: Cornelius Fudge, Rufus Scrimgeour and Pius Thicknesse. Umbridge was designated as Defense Against the Dark Arts teacher at the Hogwarts School of Witchcraft and Wizardry by order of the Ministry in 1995 and was later promoted to Hogwarts High Inquisitor and eventually Headmistress. This was part of Fudge's effort to keep the school and Harry under hid surveillance. She was removed from these positions later on in 1996 and returned to the ministry, reappearing as a minor antagonist in the final book/films Harry Potter and the Deathly Hallows, working as a judge under Lord Voldemort's supremacist reign. She sent Muggle-Born Wizards & Witches to Azkaban for supposedly "stealing" magic from Pure Blooded ones. After Voldemort's death at Harry's hands and the reformation of the Ministry of Magic by Kingsley Shacklebolt, Umbridge was arrested, tried, convicted and sent to Azkaban for life for her crimes against Muggle-borns as not all of them survived.
She was portrayed by Imelda Staunton in the Order of the Phoenix and Part 1 of the Deathly Hallows films.
She is "The Heavy" of The Order of the Phoenix, with Voldemort as the Big Bad.