The Dragon-Emperors have fallen. The Imperial Wars have drained the once-proud nobles of the Heavenly Empire. Strife, strife beyond imagining has depleted their strength. Now, the cities of the Seven Sorrows must do without their emperor, without their nobility, and without the caste of sorcerer-lords that once ruled them. From the wreckage, the Heavenly Empire re-emerges onto the world stage... in a time of nation-states, absolutism, and mercantile adventurism.
This is a pitch for a 5th Edition D&D setting. It would use modified 5e rules, backgrounds, and races. Rather than a traditional pre-industrial feudal period, the Heavenly Empire posits a modern, industrializing, landscape with political formations that are much more similar to those in the modern period. States, as we now conceive of them, play a huge role, rather than the feudal model of personal loyalty.
BACKGROUND. Before the Imperial Wars, the Heavenly Empire was made and governed by the Dragon-Emperors. These lords were literally dragons, descended from the Primal Dragons who originally divided up the world. In other regions, those dragons were overthrown by the so-called slave races: men, elves, dwarves, gnomes, halflings, orcs. The tieflings, heirs to the demonic sorcery of the Old Ways, served as the dragon's lieutenants in the Heavenly Empire, and the royal houses in many other lands.
The world was divided between the Empire and the Barbarian States. Those Barbarian States now sit at parity with the former Empire, for the Heavenly Empire has fallen. The Imperial Wars consumed her, with dragon-lords vying for power. The great houses are all but exterminated, and only a handful of dragons remain. The mightiest servants of the Empire, the dragonborn, retain much of their rights and privileges, and make up the burgeoning burgher and merchant classes, along with some of the newly emancipated slave races.
The Imperial Wars began with the death of the Gaolong Emperor and the war of his seven children. Each child took for their base of power one of the seven great cities of the Empire, along the vast and winding river that cuts through its heart and is fed by six lesser rivers: the legendary Seven Sorrows. For that reason, the Imperial Wars are also known as the War of Seven Sorrows, and the heirs to the throne were often colloquially known as "the Sorrows."
After centuries of internecine warfare, the Sorrows were no closer to the throne; whenever a contender died, other pretenders stood up to join the fray in their place. It was, at last, the High Landmenn Council of the great financial city of T'ai Sha that overthrew them and drove out the living Sorrows. A compact between the powerful tiefling sorcerers and dragonborn merchantile class resulted in the expulsion or execution of the living dragons.
Of course, this rebellion, called alternately the T'ai Sha Rebellion or the Devil's Bargain, made liberal use of a surge of anti-draconic feeling in the slave races. The Chained, as they called themselves, formed a faction to themselves, and when the dragons were executed or gone, they threatened to swamp the great cities in violence. The Landmenn, the most powerful of urban burghers in the realm, and the sorcerers quelled the Chained Revolutions and established the Writ of Perpetual Freedom: in exchange for ending their fight, the slave races of the Empire would agree to be freed from servitude and land-bondage.
This worked in most places, except for the city of T'ai Sha. The Chained there had a strong backbone of support from young burghers and students at the University of Celestial Knowledge, where the sorcerers were trained. They seized the city in the name of what they called "Universal Brotherhood", executed every priest within the walls, set her junks on fire, and proceeded to take control of all land and goods for the Universal Revolt.
They were eventually put down by powerful dragonic forces, recruited from amongst the ranks of the former restorationists. The Dragon-General Tunwen attacked T'ai Sha with his iron steamships and flying wizards, and put an end to the Universal Brotherhood -- or so he thought.
Tunwen was named the Grand Marshal of the new Republic of T'ai Sha, but before three years were out, escaped members of the Universal Brotherhood could be found preaching rebellion in the provinces. They warned that the so-called "free wage labor" of the new Republic was little different from the chains of the Empire. "One is made of iron, one of gold, but both bind," Sister-Scholar Lema warned.
The Brotherhood could not stand against the uniting armies of the new Republic, and were driven into the Red Mountains, far to the west, where they raised their banner of rebellion. To this day, the Revolutionary Red State holds the richest iron, copper, tungsten, coal, and oil lands in the former Empire. The Republic of T'ai Sha considers the Red State to be a carbuncle within its borders, an existential danger. The other nations of the world agree: so long as the Red State continues to exist inside of the Republic like a tumor, it gives the lower classes of the world a rallying cry and a red banner to wave.