The Land of Diabolos and his servants, Thanatos and his Azrael. Hades is divided in 3 layers:
Necron/The Necropolis, The First Layer of Hades, the city of the dead. Thanatos and his Azrael reside here.
Erebus, The Second Layer of Hades, The Land of Darkness. Ruled by the Goddess Eona.
Pluton, The Third Layer of Hades: Contains Diabolos' Palace in the City of Pandemonium.