The underworld is hidden in the earth. It is the kingdom of the dead and ruled over by Hades. Hades is a greedy god who is greatly concerned with increasing his subjects. Those whose calling increase the number of dead are seen favorably. The Erinyes are welcomed guests. He is exceedingly disinclined to allow any of his subjects leave.

For most, life in the underworld is not particularly unpleasant. It is rather like a miserable dream, full of shadows, without sunlight or hope. A joyless place where the dead slowly fade into nothingness.

Geographically, the underworld is surrounded by a series of rivers: The Acheron (river of woe), The Cocytus (river of lamentation), The Phlegethon (river of fire), The Styx (river of unbreakable oath by which the gods swear), and The Lethe (river of forgetfulness). Once across the rivers an adamantine gate, guarded by Cerberus, forms the entrance to the kingdom. Deep within the kingdom is Hades vast palace, complete with many guests.

Upon death a soul is lead by Hermes to the entrance of the underworld and the ferry across the Acheron. There is a single ferry run by Charon to take the souls across the river. Only those who can pay the fare, with coins placed on their lips when buried, receive passage. The rest are trapped between two worlds. The souls then enter through the gates. Cerberus will allow all to enter but, none to leave. The souls then appear before a panel of three judges, Rhadamanthus, Minos I, and Aeacus, who pass sentence. The very good go to the Elysian Fields. Others are singled out for special treatment. Sisyphus and Tantalus being prime examples of the later.

Hades - Lord of the Underworld

In Greek mythology, Hades (the "unseen"), the god of the underworld, and a son of the Titans, Cronus and Rhea. He had three sisters, Demeter, Hestia, and Hera, as well as two brothers, Zeus the youngest of the three and Poseidon his older brother, the six of them were Olympian gods.

Upon reaching adulthood, Zeus managed to force his father to disgorge his siblings. After their release the six younger gods, along with allies they managed to gather, challenged the elder gods for power in the Titanomachy, a divine war. Zeus, Poseidon, and Hades received weapons from the three Cyclopes to help in the war: Zeus the thunderbolt, Hades the Helm of Darkness, and Poseidon the trident. The night before the first battle, Hades put on his helmet and, being invisible, slipped over to the Titans' camp and destroyed their weapons. The war lasted for ten years and ended with the victory of the younger gods. Following their victory, according to a single famous passage in the Iliad (xv.187–93), Hades and his two brothers, Poseidon and Zeus, drew lots for realms to rule. Zeus got the sky, Poseidon got the seas, and Hades received the underworld, the unseen realm to which the dead go upon leaving the world as well as any and all things beneath the earth.

Hades obtained his eventual consort and queen, Persephone, through trickery, a story that connected the ancient Eleusinian Mysteries with the Olympian pantheon. Helios told the grieving Demeter that Hades was not unworthy as a consort for Persephone.

Despite modern connotations of death as evil, Hades was actually more altruistically inclined in mythology. Hades was often portrayed as passive rather than evil; his role was often maintaining relative balance.

Hades ruled the dead, assisted by others over whom he had complete authority. He strictly forbade his subjects to leave his domain and would become quite enraged when anyone tried to leave, or if someone tried to steal the souls from his realm. His wrath was equally terrible for anyone who tried to cheat death or otherwise crossed him, as Sisyphus and Pirithous found out to their sorrow.

Because of his dark and morbid personality, he was not especially liked by either the gods or the mortals. Feared and loathed, Hades embodied the inexorable finality of death: "Why do we loathe Hades more than any god, if not because he is so adamantine and unyielding?" The rhetorical question is Agamemnon's (Iliad ix). He was not, however, an evil god, for although he was stern, cruel, and unpitying, he was still just. Hades ruled the Underworld and therefore most often associated with death and was feared by men, but he was not Death itself — the actual embodiment of Death was Thanatos.

Symbols and weapons of Hades:  The Helm of Darkness, a bident, and a skull.

Persephone - Queen of the Underworld

Persephone was the Queen of the Underworld, consort of Hades and the daughter of Demeter and Zeus.

Her story has great emotional power: an innocent maiden, a mother's grief at the abduction, and the return of her daughter. It is also cited frequently as a paradigm of myths that explain natural processes, with the descent and return of the goddess bringing about the change of seasons. In a text ascribed to Empedocles describing a correspondence between four gods and the classical elements, the name Nestis for water apparently refers to Persephone. "Now hear the fourfold roots of everything: Enlivining Hera, Hades, shining Zeus. And Nestis, moistening mortal springs with tears".

Of the four gods of Empedocles' elements it is the name of Persephone alone that is taboo, for the Greeks knew another face of Persephone as well. She was also the terrible Queen of the dead, whose name was not safe to speak aloud, who was named simply "The Maiden".

In The Odyssey, when Odysseus goes to the Underworld, he refers to her as the Iron Queen. Her central myth, for all of its emotional familiarity, was also the tacit context of the secret initiatory mystery rites of regeneration at Eleusis, which promised immortality to their awe-struck participants - an immortality in her world beneath the soil, feasting with the heroes beneath her dread gaze.