Underworld

The Underworld (冥界 Mekai) is the home of the Devils and Fallen Angels.

Appearance
It has the same size as the human world but has a larger landmass, as there are no oceans. The sky is purple at both day and night. The Underworld was originally split into two regions: The Devils' Region and the Fallen Angels' Region, which ended in Volume 4 after the creation of the peace treaty between the leaders of the three factions.

Lilith
The current Capital of the Satan territory.

Lucifaad

The old Capital of the Satan territory.

Gremory Castle
The home of the Gremory Clan.

Cocytus
The deepest part of the Underworld that is connected to the Realm of the Dead.