Styx was the Titan goddess of the underworld river Styx and the eldest of the Oceanids.
She was also the daemon personification of hatred (stygos). Styx was a firm ally of Zeus in the Titanomachy, who brought her children Nike (Victory), Zelus (Rivalry), Bia (Force) and Cratus (Strength) to stand beside the god in battle. Zeus rewarded her by making her stream the agent of oaths which bound the gods.
The river Styx was also a corrosive Arcadian stream which allegedly flowed forth from the underworld.