Hades

"All of mortal life ends here: either to be tortured for eternity in the Fields of Punishment due to the foolish decision of offending a god, wander aimlessly and mindlessly for the rest of the afterlife in the Fields of Asphodel by virtue of having an uneventful life with no deeds or cruelty to their name or, on a twist of fate, enjoying unending bliss in the Fields of Elysium".

Manifestation

The Greek underworld is an otherworld where souls go after death. At the moment of death, the soul is separated from the corpse, taking on the shape of the former person, and is transported to the entrance of the underworld, where Charon, the deity in charge of transporting the souls of the dead will take them across the River Styx.
The underworld itself—also known as Hades, after its patron god—is described as being either at the outer bounds of the ocean or beneath the depths or ends of the earth. It is considered the dark counterpart to the brightness of Mount Olympus with the kingdom of the dead corresponding to the kingdom of the gods. Hades is a realm typically invisible to the living, made solely for the dead.
There are six main rivers in the underworld. Their names were meant to reflect the emotions associated with death.

• The Styx is generally considered to be one of the most prominent and central rivers of the underworld and is also the most widely known out of all the rivers. It's known as the river of hatred and is named after the goddess Styx. This river circles the underworld seven times.

• The Acheron is the river of pain. It's the one that Charon, also known as the Ferryman, rows the dead over according to many mythological accounts, though sometimes it is the river Styx or both.

• The Lethe is the river of forgetfulness. It is associated with the goddess Lethe, the goddess of forgetfulness and oblivion. In later accounts, a poplar branch dripping with water of the Lethe became the symbol of Hypnos, the god of sleep.

• The Phlegethon is the river of fire. This river leads to the depths of Tartarus.

• The Cocytus is the river of wailing.

• Oceanus is the river that encircles the world, and it marks the east edge of the underworld.

The souls that enter the underworld carry a coin under their tongue to pay Charon to take them across the River Styx. Charon may make exceptions or allowances for those visitors carrying a certain Golden Bough. Although Charon embarks one group after another, some souls he grimly turns away. These are the unburied which can't be taken across from bank to bank until they receive a proper ceremony.
Across the river, guarding the gates of the underworld is Cerberus.

Localization

Typically the way to reach the Underworld is through Death itself. Upon dying, and if there is no interference with the passing of the soul, the spirit of the deceased will reappear where Charon may be stationed.
However, there are places in the Material Plane that have a connection to the Underworld, strong enough that they will be able to create a path either directly to some area of the Underworld or at the very least to Charon's Station.

Type

Metaphysical, Divine