Margaret Wyndham
Margaret Wyndham was headmistress of Winterborne School after Gavin Purcell's imprisonment. She applied for the job because she was suspicious of her twin sister Barbara Taploe's murder at the school, believing that the police report and P.R.O.B.E.'s involvement meant that there was more to it than met the eye. As part of her revenge against Isaac Greatorex, she stole his grimoire.
She called Andrew Powell to her office offering him support and, if he wanted, a deferral of his upcoming exams due to the incident with Christian Purcell and the Winterborne murders. She phoned Liz Shaw and invited her to the school to discuss Barbara's death, later presenting her with Greatorex's grimoire and telling her that he would need it in order to resurrect himself. When he took possession of Gavin Purcell, she used a spell to cast him out, defeating him and avenging Barbara. (HOMEVID: Ghosts of Winterborne)