A character published by Marvel Comics.

The actual origin of Agatha Harkness has yet to be revealed, but over the years much has come to light of the past of this elderly, white-haired woman. She is reported to be as much as 200-centuries old and she is known to have been the leader of a coven of witches in a New England town called New Salem. She is the mother of a warlock called Nicholas Scratch and grandmother to a group of magically-enhanced individuals known as the Salem's Seven.

Agatha first appeared in Fantastic Four #94. She acted for a time as the governess of the infant son of Reed and Susan Richards, Franklin. The writers at the time never sufficently explained why such a scientifically-oriented family would employ a sorceress as their nanny. Her familiar, a black cat named Ebony had the ability to transform into a huge panther when attacked or when Agatha was in danger.

Eventually, Franklin grew to an age where he did not need to be watched by a nanny, and Agatha turned her attention to another member of the super-hero community. Wanda Maximoff, the Scarlet Witch, began to explore her mystic heritage, when her mutant power, her hex bolts, were discovered to be too draining and unpredictable. Agatha trained Wanda in the arts of magic, soon making her not just a witch in name only.

Agatha was attacked by her grandchildren the Salem's Seven and put on trial for being a good witch. The members of the Salem's Seven (Brutacus, Gazelle, Hydron, Reptilla, Thornn, Vakume, and Vertigo) found her guilty burning her at the stake for her crimes.

Agatha did not let this hold her down however. She was able to aid her former pupil, the Scarlet Witch, when Wanda came into conflict with the Salem's Seven years later. Even later, she actually came back to life, to aid the Scarlet Witch when she was being manipulated by the villain Immortus. To this day, Agatha is one of the Scarlet Witch's most trusted advisors.