Locusta was a notorious maker of poisons in the 1st-century Roman Empire, active in the final two reigns of the Julio-Claudian dynasty. She supposedly took part in the assassinations of emperor Claudius and his son, Britannicus. She was a favorite of emperor Nero for several years, and Nero had her provide training to other poisoners in his service.
The part that is uncertain is if she enjoyed poisoning or if it was her profession as a contract killer. It should be noted in the translation below, that she is regarded as an acclaimed poisoner BEFORE she poisons Claudius or Brittanicus.