Miss Foster is a schoolteacher on Éilís Mór. Lord Donnán considers her to be a resident expert on the island's history. She provided Wakefield with background information regarding the Festival of Reunion, the Cronemeadan, and the heir of Laidcend. When Wakefield expressed an interest in Kieran's disappearance, she suggested that he talk to Kieran's classmates.
Miss Foster seemed like a reasonable person, but she clearly believed at least some of the folk tales about Éilís Mór. She advised Wakefield to not approach the hole in the hills, since the Crooked One was said to live at the bottom, and it had not been fed in some time. Wakefield also discovered occult songs and books in her classroom.
When Wakefield returned from the Solitary House, Miss Foster had vanished, along with everyone else in the village.