During her time at Hogwarts, Umbridge grows in power and is appointed High Inquisitor by the Minister for Magic in an attempt to control the school.

Despite being assigned as the Defence Against the Dark Arts teacher, Umbridge refuses to teach anything practical in the subject, which leads to the formation of Dumbledore's Army as a way for the students to learn how to defend themselves.

Umbridge is physically described in the narrative as a fat, toad-like woman with a wide slack mouth and a large bow that is often in her hair.

Umbridge used this position of power to satisfy her hatred of part-humans, for example through new Anti-Werewolf Legislation which made it nearly impossible for Remus Lupin to find a new job after resigning his post as Defence Against the Dark Arts Professor at Hogwarts in 1994.

After rumours of Voldemort's return and the increased paranoia of Cornelius Fudge, Umbridge set two dementors on Harry Potter and his cousin Dudley Dursley in Little Whinging in an attempt to get him expelled from Hogwarts for use of magic outside of school.

She began interfering with the students learning at Hogwarts by refusing to teach any practical applications despite her post as Defence Against the Dark Arts professor.

Due to the apparent return of Voldemort that was being silenced by the Ministry, students such as Harry, Ron Weasley, Hermione Granger and Dean Thomas began openly opposing Umbridge's insistence on theoretical applications.

This resulted in Dumbledore's Army members Harry, Ron, Hermione, Neville Longbottom, Ginny Weasley and Luna Lovegood being rounded up by the Inquisitorial Squad and held in her office.

[5](p 848) After Voldemort was sighted in the Ministry of Magic by numerous people including Fudge, Dumbledore was reinstated as Headmaster at Hogwarts, and Umbridge was sacked.

Following Alastor Moody's murder, Umbridge somehow obtained possession of his magical prosthetic eye and had it affixed into the door to her office as a way of terrorising Ministry employees and reminding them she was observing them at all times.

After Voldemort's defeat by Harry at the Battle of Hogwarts and the restoration of the Ministry of Magic by the new Minister, Kingsley Shacklebolt, Umbridge was sentenced to life imprisonment in Azkaban for her crimes against Muggle-borns.

[4] Umbridge is depicted in the novels as being an evil, cruel, authoritarian, power-hungry, bigoted and despicable woman who represented the worst of political power, under a saccharine image filled with kittens, fluff, and girlishness.

Umbridge is also depicted to be a prejudiced person, despising half-breeds and Muggle-born witches and wizards to the point of firing Hagrid due to his half-giant birth status.

Umbridge was a "pure-blood supremacist" and attempted to mask her half-blood status, often lambasting her Muggle mother and Squib younger brother.

Dolores Umbridge has been called one of the most despised fictional characters of all time due to her authoritarian stance and dictatorial presence, as well as her racist attitudes and torturing of children.

[6][7][8][9]IGN ranked Umbridge as the 17th best character in the franchise:This is a woman who thinks the appropriate way to punish a student involves making him perform a ritual which, thanks to magic, causes him to bleed over and over again – one of many despicable acts.

One needn’t be a child to remember The Really Scary Teacher, the one who terrified us so badly that we dreaded the walk to school in the morning, and we turn the pages partly in fervent hopes that she will get her comeuppance ... but also in growing fear of what she will get up to next.

[13][14] Former Prime Minister of the United Kingdom Margaret Thatcher was an influence on the way the character was portrayed in the film adaptations, according to director David Yates and actress Imelda Staunton.