Hester Hawthorne
From Tardis Wiki, the free Doctor Who reference
Olive Hawthorne's grandmother was the grandmother of both Olive and Poppy Hawthorne. She died when the girls were young but before she did, she gave Olive a necklace with symbols on it that resembled those on the grimoire she would later be given by her great-aunt, Lobelia. (HOMEVID: White Witch of Devil's End)