The Necromancer Hordes

Prompt 7: Somewhere in your world describe a culture who lives by/near or within an ocean/desert/or other expenses
The Necromancer Hordes
The necromancer hordes are evil humans who dwell in nine cities throughout the northern desert. They are descendants of the Undying Khan’s original Horde that ruled the Northern empire for over a thousand years. By the end of the imperial age, the Horde had become so consumed by the dark necromantic magic that the Undying Khan had imbued them with that they were almost completely dependent on them.
From an early age, children are trained in basic magics and by their late teens, they are expected to have learnt to control the dead, demonic creatures of the shadowfel. At age 18 they lose the protection of their masters and are expected to be able to survive under their power. If they have not mastered the basic powers expected in the Horde, they will be consumed by the creatures that serve the horde. The horde does not mourn the loss of weak members, if they cannot stand on their own the children are of no use to the Horde.
All members of the Horde seek power, through their dark magical arts, above all else, any opportunity to take out a rival is sought out and seized whenever it presents itself. This has made the elders of the cities very powerful and very crafty, it has, however, decimated the population of the horde. Few if any cities have living human populations greater than 500 people. As such the horde has taken extreme measures to control the population, all teens must have at least one child before 18 years of age and all males must participate in a breeding program. The program is supported by slavery, leaving the care of the children in the hands of slaves, overseen by the more intelligent and reliable undead or demonic creatures to ensure the slaves do not harm the children or turn them against the horde. Education is completed by a mentoring arrangement between the child and a horde member as soon as they are old enough to begin using magic. The mentoring is randomly assigned and due to the breeding programs and method of care for the children, no member of the Horde knows, nor cares if the mentor is their child or not. The task is seen s a bothersome necessity and the children are badly treated and encouraged to compete against others, embedding the cultural norm of cutthroat competitiveness and lust for power.
Day-to-day duties are completed almost exclusively with magic, those manual tasks that must be completed are completed by the undead or demonic minions of the horde. The Horde members themselves spend their days either finding ways to increase their power and knowledge of the dark arts or carrying out the orders of the dark lord. If not drawn together by a common cause or task the horde members would likely only interact with each other to try to destroy one another. A delicate balance is held by the treat of the dark lord's wrath, the mutual and begrudged need for others to complete more complex magical tasks and rituals, and the common goal to release Demogorgon on the world.
The Horde worship Demogorgon as their one true god and seek to unleash his divine corruption on the world. They view the Dark Lord as Demogorgon’s prophet on the material plane and believe he has direct contact with Demogorgon.
Each city is ruled by a lich, a former elder of the horde, raised after death to live and rule as a powerful undead sorcerer. The liches are generals in the dark lord's army and command large forces of undead, demons and other evil creatures under their control or the control of the citizens of their cities. They are advised by a council of nine elders who are the oldest and most powerful necromancers in the cities. The council potions are highly prised positions of power and many people kill to get a position on the council. It is both a great position of power and a dangerous seat that opens the members as targets to be usurped. Thus, the weight of power in the council is given to those who hold their positions the longest. Some ruthless necromancers have held the council head for as much as ten years, though this is rare and most died in 3-4 years.