Author J.K. Rowling has released a story on her website Pottermore.com in time for Halloween, reports Time.

The story revolves around one of Harry Potter's foes, Dolores Umbridge, who was introduced to readers in "Harry Potter and the Order of the Phoenix in 2003." Imelda Staunton played the character in the movie adaptation of the book.

The 1,500 word biography tells the story of Umbridge, a former professor at Hogwarts School of Witchcraft and Wizardry and served as the Senior Undersecretary to the Minister for Magic. It is worth noting that apart from Lord Voldemort, Umbridge is the only person to leave a mark on Harry Potter.

Rowling penned an essay in conjuction with the story, says The Hollywood Reporter.

In the essay, Rowling described Umbridge as "one of the characters for whom [she] feel the purest dislike."

"The woman in question returned my antipathy with interest. Why we took against each other so instantly, heartily and (on my side, at least) irrationally, I honestly cannot say," Rowling added, noting Umbridge's "pronounced taste for twee accessories," like "a tiny little plastic bow slide," pale lemon in color."

"I have noticed more than once in life that a taste for the ineffably twee can go hand-in-hand with a distinctly uncharitable outlook on the world," Rowling wrote.

Renowned American author Stephen King, in his review of "Harry Potter and the Order of the Phoenix" for Entertainment Weekly, wrote that "the gently smiling Dolores Umbridge, with her girlish voice, toadlike face, and clutching, stubby fingers, is the greatest make-believe villain to come along since Hannibal Lecter."

The piece about Dolores Umbridge is part of the many updates and writings made by Rowling for Pottermore in time for Halloween. There are also accounts on the characters who served as Minister for Magic, a preview of magical creatures Thestrals, Rowling's personal say on the character Sybil Trelawney, the history of the prison of Azkaban and more.