The Desert region is a land in the Monster Girl Encyclopedia world filled with sand and ruins. Once home to a great human kingdom, the desert is now a scorching wasteland inhabited mostly by treasure hunters and Egyptian-style monsters, including sphinxes and pharaohs.
In ancient times, before even the age of the former Demon Lord, the realm was one of the greatest human kingdoms, and its leaders were blessed by the previous Chief God to guide mankind. However, the desert's golden age eventually ended and the pre-monster girls monsters overran the kingdom, while the rulers "were forced into slumber" . With the monster's presence came demonic energy and, once the current Demon Lord rose to power, mana corruption, transforming the slumbering human rulers into pharaoh monster girls.
Although the pharaohs fought against the monsters in their original lives, their attitude to monster girls (and vice-versa) is much more co-operative in undeath. Anubis and mummies take it upon themselves to guard the pyramid-tombs while their queens sleep. If the pharaoh does wake up, they set about returning their lands to their former glory as bright green demon realms, with verdant oases and human-monster towns. Not all monsters are as welcoming to the return of the rulers of old: apophes prefer to make their own kingdoms or conquer the kingdoms of the pharaohs, while khepris may serve either a pharaoh or apophis, or even an incubus king. The desert today is therefore a patchwork of different states: khepri-incubus kingdoms, green pharaoh countries, dark demon realms under expansionist apophis queens, and sandy ruins picked over by human thieves and adventurers.