|“||Well done. Complimenting Agatha like that. Now she'll like you. It's no good if Agatha doesn't like you. She'll put stones in your porridge.||”|
Agatha was from a family of Sighted mundanes that had served Shadowhunters for generations. By 1878, Agatha was middle-aged and had been working at the Institute in London for a long time, enough that she was familiar and on very good terms with its residents. She was also trained in self-defense. Though she was mainly the cook, she also served the residents and cleaned the Institute, along with the maid and her good friend, Sophie Collins, and, occasionally, the driver and caretaker Thomas Tanner.
Agatha was by the entrance of the Institute when Axel Mortmain and a number of his automatons arrived to take Tessa Gray and the Pyxis. An automaton held her down, simply because she was there, and stabbed her in the chest, killing her almost instantly. Sophie was devastated by her death and had to be pried away from her corpse. When Will returned to the Institute and found her body, he closed her eyes.
Joined with the funeral of the other Shadowhunters recently killed in the battle against Alexei de Quincey, the Clave agreed to have her and Thomas's bodies burned and their ashes scattered in the Silent City—typical Nephilim funeral rites, an honor rarely given to non-Shadowhunters. Eventually, the Institute was given a replacement cook in Bridget Daly.
- Clockwork Angel (first appearance)
- Clockwork Prince (mentioned only)
- Clockwork Prince: Manga (mentioned only)
- Agatha smoked pipe and knew how to sew.