Harry Potter fans were in for a treat on Friday (31st October) when J.K. Rowling posted a new story on Pottermore.com detailing the background of the series' most disliked character, Dolores Umbridge.

Jk Rowling
J.K. Rowling at the premiere of Harry Potter and the Deathly Hallows: Part 1.

Read More: J.K. Rowling To Bring Dolores Umbridge Out Of Retirement For Halloween Pottermore Special.

There's what you need to know about Dolores Umbridge:

- Umbridge had a troubled upbringing. Her father was a wizard and her mother a Muggle. She had a squib brother and blamed her mother for her brother's lack of magical abilities. When Umbridge was 15, things at home reached breaking point and her mother and brother left the family, returning to the Muggle world never to return.

- Umbridge left Hogwarts, where she was enrolled in Slytherin house, and was employed at the Ministry of Magic. She soon rose through the ranks as she was efficient but still deeply unpleasant. 

- She attempted to find a husband from amongst her superiors at work, believing this would earn advancement through romantic connections. Unfortunately for Umbridge her efforts proved unsuccessful.

Imelda Staunton
Imelda Staunton played Umbridge in the Harry Potter films.

- Umbridge further gained advancement by playing on the fears of Minster of Magic Cornelius Fudge and gained appointment as Inquisitor of Hogwarts by playing on his fears and insecurities about his position. 

- Her views concerning the treatment of Muggles and any 'non-human' drew the attention of the Death Eaters who infiltrated the Ministry. They gave her more authority and she was placed in charge of the Muggle Born Registration Committee.

- After the fall of Lord Voldemort, Umbridge was placed on trial for working with Voldemort's regime. She was convicted of torture, imprisonment and the deaths of several people (as some of those she sentenced to jail in Azkaban died whilst imprisoned). 

- Rowling's Umbridge is partially based on a teacher she found difficult to like. The unnamed teacher had a habit of wearing frills and girlish accessories - much like Rowling's Umbridge - but was not 'sadistic or malicious' as the character is. 

Read More: J.K. Rowling Does Both Trick And Treat With Six New Pottermore Stories.

JK Rowling
Jk Rowling at the 2011 BAFTAs.