Metum the devoid is a female demon who existed from at least the Second Age and who was mentioned in one of Primrose's books. Unlike other demons, Metum thrives on the misery of others, gaining power from hopelessness and misfortune. Some inhabitants of Senntisten blamed Metum for their misery, including a man who stubbed his toe every morning when leaving bed and a woman who burned all of her food while cooking.
Joss, Primrose's father, gave his daughter the ability to summon any character she liked from her stories, including Metum. When Primrose summoned Metum, she found that she did not like the demon, so she banished her.
Megan, Primrose's mother, found a letter to Sloop, Joss's former apprentice, hidden within a book she was going to sell. In a rage, she turned back around, gathered all of Primrose's books, and burned them in the fireplace. The magic within the tomes caused a backlash which released Metum, allowing her to possess Megan. Having gained control of Megan, Metum proceeded to use the Needle and its guardian Gail to travel back in time, reliving the same month over and over on the grounds of protecting Primrose. When Primrose found out, she started travelling back in time as well in order to kill herself and spare her mother grief, which Gail was fully aware of. Megan, upon discovering this, stabbed Gail, causing the Needle's guardian to use the power to freeze time in the hopes that somebody would come by and investigate.
Metum was later banished by the World Guardian, who had used the Needle's power to figure out what had happened.
- Metum is the accusative singular form of "metus", a Latin word meaning fear and dread.