The River of Hades is a mythical river located in the underworld. It is made up of three rivers: Acheron (7 letters), LETHE (5 letters), and Styx (4 letters). Acheron is known as the river of sorrow, LETHE is the river of forgetfulness, and Styx is the river of hatred. Together, these three rivers form the River of Hades, which is believed to be the boundary between the world of the living and the world of the dead.