Phlegethon

The Phlegethon (Greek Φλεγέθων - "The Flaming "), even Pyriphlegethon, in addition to Styx, Acheron, Lethe, Cocytus, and a river and thus also a river deity of the underworld in Greek mythology. The Phlegethon leads no water, but flames that burn everything and never go out. In some representations it is said that he leads boiling blood.

According to Plato's Phaedo the Pyriphlegethon is near its source a lake in the middle of a level of fire, from which he carries with red-hot stones and boiling mud. It flows then circling in the depths of the earth, before it finally empties into the Tartarus. It runs close to the Acherunischen lake formed by the river Acheron, but does not lead to this. The exiting with volcanic lava activities should come from its river bed.