Amarantz was captured by Grey Guards alongside her husband and taken to the Shadowlands. While she claimed to be beaten and abandoned by the Grey Guards near the border, she was actually taken to the Factory. Servants of the Shadow Lords experimented upon her with a prototype Carrier Worm that took away her hearing.
Under the supervision of the Shadow Lord, Amarantz returned to the Del Palace as a cook. As a cook, she easily poisoned the food of important people. Using her connections to her former friends, Amarantz was able to learn of Marilen through Josef. She attempted to poison her, but Marilen was warned by the great Amethyst of the poison, and Jinks later ate the poisoned food instead.
Thinking she had succeeded in killing Lief's bride, Amarantz then proceeded to poisoning Steven, Lindal, and Doom, using small poisoned cakes. Luckily Sharn was able to stop them before anyone could eat the cakes. Amarantz mocked everyone once she had been exposed, and dropped hints of the Carrier Worms. She told that 'many more' would come. After that she ate one of the poisoned cakes, and the Carrier Worm attempted to flee, only to be crushed by Doom.
Now freed from the Shadow Lord's control, Amarantz managed to speak to Sharn, expressing joy in waking from a horrible nightmare, before dying in her arms.
While under the control of a carrier worm, Amarantz had only one goal: to do the Shadow Lord's will. The carrier worm controlled her personality and how she acted. For example, she lied about how she managed to evade entering the Shadowlands. She also prepared poisoned food for Marilen and others.
Amarantz was a reasonable skilled cook because Sharn offered her a job as palace cook. She also mastered the craft of potter since she had worked in the pottery for most of her life. It is likely that Amarantz was able to ride a horse since she owned one. However, it is never confirmed in the books that she could ride a horse.