The Black Lands is a small region between the Southern Domain and Western Desert. It is formed as a result of an immortal talisman being destroyed and falling down onto the ground, becoming a celestial soil that makes up the entire region.
In the Black Lands there were two great powers, sort of like empires. One was the Black Lands Palace, the other was the United Nine.
The United Nine was a group of allied cities controlled by different Cultivator Clans. Of the two, however, the Black Lands Palace was the most frightening. Its Cultivators wore masks, the colors of which indicated the level of their Cultivation base.
Azure masks represented Core Formation. Silver masks represented Nascent Soul. Gold masks represented Dao Children.
The Black Lands Palace ruled by force in the Black Lands. It was referred to as the number one power, and was known to have the support of the Western Desert. Because of that, even the Sects of the Southern Domain feared the Black Lands Palace.
A Dao Child from the Black Lands Palace was like a Chosen of the Heavens. One word from him could determine life or death for these Cultivators. He was the Heavens, they were nothing but bugs.
This was where the numerous tribes from the Western Desert who was able to pay an 'entrance tax' in the form of a demon spirit, migrated to when the apocalypse hit. A demon spirit was required to enter the Ruins of the Ancient Demon Immortal Sect that opens only every 200 years.