The Empire of Decadence was a caste-based human monarchy ruled by pharaohs that is believed to have arose shortly after a world-wide calamity, referred to as 'The Apocalypse', which wiped out the original kingdoms of Laurasia. The use of slaves was common, gold and lapis lazuli were highly valued, and the practice of mummification was common, with the dead being placed in elaborate tombs.
The Empire was traditionally polytheistic and worshipped an animal-headed pantheon of deities; at one point it was conquered by a Bhaal-worshipper, who started a short-lived dynasty founded on the concept of monotheism.
Several means of communicating with those of the Empire have been uncovered. The Tomb of Sekhemkhet has a summoning circle within it which can be used to communicate with the spirit of Sekhemket, a half-orcish pharaoh of the Empire. The spirit of a vizier of the Empire resides in a staff that was discovered in the Tomb of Amenemhat, and the ghost of a queen of the Empire of Decadence was discovered in the Grave of the Betrayers. In addition, a sphinx informed Alejandra that she is descended from the people of this Empire, a heritage which she has just begun to reclaim.