Letheus was the King of Athens during the events of Young Hercules; while Jason believes him an honourable man, he rarely shows it, prizing slavery and ignoring the woes of farmers in his land. He hired the pirate Zared to bring him a group of Amazons as slaves, but they were freed by Hercules.
His father is mentioned to have been named Claudius, who did business with King Aeson of Corinth. When Claudius and Aeson died, Letheus and Jason became trade partners.