Decades before the beginning of the novel, the Witch caught a falling star which became her fire demon. Because of this, the Witch became evil. The relationship between her and her fire demon was parasitic, as the demon was draining her magic. Fifty years before the events of Howl's Moving Castle, the current King's father banished the Witch to the Waste, and the Witch bore the current King a grudge for that.
A year before the events in the novel, the wizard Howl pursued her, and later jilted her. Out of fury and the need of his head for her human puppet, the Witch cursed him so that he would be forced to return to the Waste.
She is a talented witch who was so beautiful that Howl pursued her, but after finding out that she used magic to keep herself looking young and beautiful, he left her. She is still in love with Howl, however, and uses her magical powers and henchmen to try and capture him after seeing him with Sophie. That is why she arrives at night to Sophie's hat shop, and insults her before turning her into a 90-year-old woman. As Sophie leaves her hometown in order to break the curse on her, she reaches Howl's castle. Through Sophie's pocket, the Witch uses ancient sorcery to put a powerful spell on Howl in the form of a note. The scorch marks read:'You who swallowed a falling star, oh heartless man, your heart shall soon belong to me.'
Initially the antagonist, the Witch becomes somewhat of a protagonist after Madame Suliman lures her to the castle to drain her of her magical powers, restoring the Witch to her actual appearance and age.
The Witch of the Waste is far more terrifying in the novel as she serves as the antagonist. In her first appearance in the novel, she curses Sophie by turning her into an old woman (she mistakes her for Lettie). Howl has spent the past year hiding from the Witch while trying to find Prince Justin and Wizard Suliman. Near the end of the novel, Howl kills the Witch when arriving at the Waste to rescue Sophie.
The Witch of the Waste was a very powerful and feared witch with a vast arsenal of magical abilities. She used to be a good witch until she made a pact with a fire demon. The relationship between her and the demon became parasitic and began to drain her and her magic. Even though the demon had drained her magic for many years, she was still capable of casting curses, but was not able to reverse them. She cursed Sophie because of her jealousy towards Howl's interest in Sophie to a 90-year-old hag, she is capable of some form of telekinesis, as seen when she opened the locked door to Sophie's hat store. Due to that, Madame Suliman lured her in order to drain her magical powers and restoring the witch into her actual appearance. She is currently powerless.
The Witch of the Waste is voiced by Akihiro Miwa in the Japanese version and by Lauren Bacall in the English-dubbed version.