Hagatha

Hagatha is the witch who resided in Kolyma and imprisoned Valanice in the Crystal Tower, due to jealousy. She is the sister of Mordack and Manannan. She is said to be the most powerful and evil of witches, and has a taste for human flesh. The skulls of her victims decorate the outside and inside of her cave.

Background
Hagatha is an old and evil witch, with poor eyesight, who lived in the kingdom of Kolyma, known for her cannibalism, and has killed many unfortunate travelers who have fallen into her clutches (placing their skulls on stakes outside of her cave, or scattered about inside). She is a vain hag who was jealous of beauty of the maiden Valanice, the daughter of the prince of Kolyma. The jealous crone whisked Valanice away from her parents. Taking her to an enchanted land, and imprisoned her in a Quartz Tower guarded by a ferocious wild beast.

Years later, after Graham journeyed to Kolyma in search of Valanice, he discovered that Hagatha, was not only Valanice captor, but that she had also stolen Milvia's magical Nightingale. He managed to enter into Hagatha's very lair, to rescue the magical nightingale from under Hagatha's wicked nose. But she was strong and powerful, he had no way to defeat her, and had to avoid her. Graham ultimately made it to the Quartz Tower on the Enchanted Island where Valanice was being kept, and rescued her from Hagatha.

Later, Manannan, her brother, kidnapped Graham and Valanice's son in revenge for Graham's deed against Hagatha. Dame Hagatha disapeared from Kolyma soon after the incident.

Derek believes that Hagatha's evil family is the cosmic balance to Graham's. Nothing had been heard of either Hagatha or Mananann since Graham destroyed their brother Mordack. He thinks that is a bad sign.

Behind the scenes
In the official King's Quest Collection trivia program, and King's Quest Companion, she is said to be sister of Mordack and Manannan. Though this fact is not brought up in any of the manuals or the other official King's Quest games.

Apparently Roberta had nothing to do with the idea, though Peter Spear and other King's Quest designers established it in the trivia game and companion;

"'I asked Roberta [...], and sorry to admit that she said she didn't remember the Black Cloak Society. It sounds cool. Perhaps she should have taken it more seriously and featured it in other games. With respect to Hagatha [being related to Manannan and Mordack]: Roberta's answer was, 'Would you like them to be related?' Then she said, 'Nope, Hagatha was her own separate person.'" - Ken Williams at SierraGamers (6-9-2003)

"...one final thing: Hagatha was never part in any discussion of a Black Cloak Society." - Roberta Williams at SierraGamers (6-9-2003)

In PG Wodehouse's "Jeeves and Wooster" books and stories, Bertie Wooster has two meddling aunts named Dahlia and Agatha. It is possible that Dahlia and Hagatha are named after these fictional characters.

Trivia

 * In the original version of King's Quest II, if you sneak up to her in her cave and type "kiss Hagatha", you'll get a humorous response: "Smack, hug, whoopie.. yuck, barf, gag."
 * If Graham walks through the screen with the entrance to Hagatha's cave several times the Batmobile will appear and drive into the cave.

Hagatha (unofficial)
Hagatha appears in fan fiction including fan games, see Hagatha (unofficial).