Amaranta was one of Straff Venture's mistresses. She was a highly skilled herbalist, specializing in poisons and antidotes. After Straff lost interest in her as a sexual partner, she became Zane's mistress.
Amaranta poisoned Straff, placing an addictive drug in his antidotes. She told Straff it would kill him if he stopped taking it, which was a lie. Straff killed her accidentally, in rage and panic.