The Styx is one of the five rivers of the Underworld, in Greek mythology.
Styx was a daughter of the Titans Oceanus and Tethys, and the mother of Nike (victory), Zelus (Zeal), Kratos (Power), and Bia (Strength). With her offspring, Styx came to the aid of Zeus in his battle against the Titans. As a reward, Zeus made Styx the goddess by whom the most solemn oaths were sworn. Styx is the nymph of the Underworld River Styx.
Sometimes Charon is said to ferry dead souls across the River Styx instead of the Acheron.