Mortasheen is a world of grisly creatures. Humankind reached its apex hundreds of thousands of years ago, and is now all but supplanted by bioengineered monsters -- some sapient, some not. Many of them live in Mortasheen City, a truly ancient anarchistic city-state the size of a small continent. They rely on the bizarre abilities of their monsters as much as they rely on any technology, training and shaping the creatures as a way of life... though often, the roles of "trainer" and "monster" are merely a social contract between equally-monstrous and intelligent beings.
The very air of Mortasheen City teems with microscopic bioweapons that could sicken someone without acquired immunity in mere hours. Feral beasts stalk the streets in broad daylight, or what little seeps through the polluted clouds. With convenient cloning facilities, death is cheap, but so is life. The city's inhabitants are ghoulish and violent, but usually not malicious: being ghoulish and violent is just their way, and they enjoy it.
The smaller nation of Wreathe offers an alternative to Mortasheen City's chaos: a dictatorship run by an AI that seeks the extermination of all life that could compete with, or corrupt, humankind. That is to say, the vast majority of sapient life on the planet. The two nations clash violently, each scarcely able to comprehend the morality of the other. Thus far, Mortasheen's irregular vigilantes and trainers have fared poorly against Wreathe's mechanized military-industrial complex, but the great city will not fall so easily...