Hades is a location in the series.
Hades, also known as the land of the dead or simply the underworld, is the Greek underworld where souls go after death. This otherworldly realm is ruled by the Greek god Hades and his wife Persephone, along with many other gods and daemons. The Roman version of the underworld was known as Avernus.
The original Greek idea of afterlife is that, 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. The underworld itself (sometimes 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 invisible to the living, made solely for the dead.
Kyuuyaku Megami Tensei
The Underworld is a secret dungeon in Megami Tensei, reached by going to a specific location in the north-central area of Valhalla B1F with Cerberus in the protagonist's stock; without Cerberus, the room only contains a description that it reeks of death, but if he is present, a man asks Nakajima if he would like to go to the Underworld. The COMP cannot be used in the Underworld, however the Mappara spell still works. Unless the Trastart spell is used to leave, Cerberus will leave the party when the exit is reached, saying he must ensure the dead cannot leave.
In Megami Tensei II, there are rooms with the description "A stagnant air is flowing here," found in Bael's Castle 2F, Shinjuku Underground, and the Lost Forest. If Bael was killed as a frog, stepping into one of these rooms will transport the party to the Underworld, where strong enemies are located. Unlike in Megami Tensei, the COMP can be used here without problem. In each section, there is a square where a Green Slime can be encountered; there is a 1/32 chance that, instead of encountering a Slime, one of the hidden Deities will be encountered: Artemis in the Bael's Castle section, Leto in the Shinjuku Underground section and Apollo in the Lost Woods section. If all 3 are obtained, they can be fused together into Zeus regardless of the protagonist's level.
Kyuuyaku Megami Tensei
|Will O' Wisp (Red)||Foul||7|
|Will O' Wisp (Blue)||Foul||4|
Megami Tensei II
|Green Slime *||Foul||1|
|Tamamo no Mae||Femme||64|
|Playable||Akemi Nakajima - Yumiko Shirasagi - Cerberus|
|Non-playable||Minotaur - Medusa - Rick - Loki - Gaia - Hecate - Izanami - Seth - Lucifer|
|Daimakyuu||Micon - Tower of Daedalus - Bien - Valhalla Corridor - Mazurka Corridor - Rotting Sea of Flames - Infini Palace - Hades|
|Terminology||Demon - Hinokagutsuchi - Magnetite - Moon Phase System - Cathedral of Shadows (Fusion) - Rag's Jewelry - Izanami Clothes|
|Lists||Demons - Items - Spells (Kyūyaku)|
|Games||Megami Tensei (Telenet) - Kyūyaku Megami Tensei|