Claire Foy as Anathema Device.
Any prowling maniac would have had more than his work cut out if he had accosted Anathema Device. She was a witch, after all. And precisely because she was a witch, and therefore sensible, she put little faith in protective amulets and spells; she saved it all for a foot-long bread knife which she kept in her belt.
“Anathema Device,” said Anathema. “I’m an occultist, but that’s just a hobby. I’m really a witch. Well done. You’re half an hour late,” she added, handing him a small sheet of cardboard, “so you’d better read this. It’ll save a lot of time.”