Elís Abaigeal Kedward (b. 1729), later known as Elly Kedward, was a half-blood witch who grew up to become quite powerful in the dark arts. The daughter of an Irish witch and a Muggle father, she was orphaned at a young age and briefly raised by an outcast wizard living in the Skibbereen hills in Ireland. When he too died during the Great Frost, and she found herself again an orphan, she was subjected to horrendous treatment, first by the Muggles who imprisoned her at Baconsthore Asylum, and later by the wizarding community when they imprisoned her in Azkaban.
After her escape from Azkaban in 1768, she stole a wand, along with numerous other supplies, and made a six month voyage aboard a sailing vessel to the New World. She arrived in the summer of the following year and made her home at the base of Mount Greylock in what would eventually become the state of Massachusetts. There, she could keep a watchful eye on Ilvermorny School of Witchcraft and Wizardry.
Behind the scenes
Elly is both named after and highly based upon the fictional Elly Kedward, who acts as the titular "Blair Witch" in the Blair Witch franchise. Some details of her past were changed, however, to fit the author's new narrative: for instance, Elly settled in Massachusetts rather than in Blair, Maryland.