|First Appearance||HTLJ: Hercules in the Underworld|
|Last Appearance||XWP: You Are There|
This stagnant waterway runs in a tunnel. That tunnel is an interplanar gateway between an air-filled cave at the bottom of the Alcyonian lake in the Known World and Underworld. The souls of the dead of the Greco-Roman culture line up here to await their turn. Charon’s skiff is the only way to traverse the gateway. You can jump in and swim (although the water is icy cold and filled with all kind of supernatural germs), but without the skiff, there’s no way for you to pass over to Tartarus, no matter how far you swim.
For all its foulness, Styx is in fact composed of holy water, thus forming an effective barrier for holding the underworld spirits back.
In the myth Styx is the name of an Oceanid, daughters of Tethys and Oceanus, the goddess of the Styx River. In classical myths, her husband is Pallas and she gave birth to Zelus, Nike, Kratos and Bia, Styx supported Zeus in the Titanomachy, where she was said to be the first to run to his aid. For this reason, his name received the honor of being a mandatory oath for the deities.