Hades

God of the underworld, so named because he was given the unseen kingdom. Brother of Zeus, when the world was divided in three, received the Underworld as his kingdom. His kingdom was entered by crossing the river Styx, ferried accross by Charon (pronounced Karon). The nether side of the river was guarded by Cerebus, the three headed dog defeated by Herecles (or Hercules as the Romans refered to him).

Greek (ha'-dez) (Haides, haides, "not to be seen"): Hades, Greek originally Haidou, in genitive, "the house of Hades," then, as nominative, designation of the abode of the dead itself. (Compare Hebrew, She'Ol, "unseen," also the abode of the dead). Originally, the underworld or the unseen realm to which the dead go upon leaving the world. The god, Hades, was named after the place, which predates him in Greek mythology.