Here is my latest idea. I've been toying with this for a while. It's inspired by modern fantasy writing as well as comics. It was inspired by various discussion on what fantasy supers would look like as well as a fantasy version of Shadowrun (which i suppose is just thieves guild). It's Chris Claremont writing Malazan: the pc's are sort of the X-Men (though I'm no X-pert, imagine the Darkling League as The Brotherhood, and the Deathless Mask as the Hellfire Club) and the world is filled with strange powers and presences with the tangible remains of old powers (the gods of old aren't completely dead, most of them are imprisoned, as spirits, in a place that's a cross between Arkham Asylum and Whispering Vault). It's an urban setting, but still with fantasy trappings. Not quite steampunk, but not just swords and shields.

The Godwar:
In the early age, the gods were those sorcerer-kings whose power transcended the mortal realm. They shaped the world inspiring followers, through fear or hope, and wrought the world, eventually, into a chessboard of their own design. They carved kingdoms, godholds, out of the land, shaping it literally into their own making through power that grew unchecked until the world seemed too small to contain them. Eventually, and perhaps inevitably, they grew bored with lesser men and a tiny kingdom and made war against each other.
Not all mortals were weak beneath the indifference of such immortals. The House of Shadows were able to steal away power of their own from the godholds and created a furtive resistance that eventually turned the mortal nmasses against their masters when they least expected. As the gods' war took hold they inspired men to see the cruel nature of the gods whose actions threatened their homes and lives. The uprising grew, painfully and bloodily, until the gods were brought down.
As the age passed the rule of the gods was replaced by the Great Houses of man. Leaders were chosen and made; the progenitors of these noble houses who, together, gave birth to the greatest empire of the modern world. But, as is the nature of power, they themselves grew distant. It wasn't long before they saw the House of Shadows as a threat to their reign and branded them heretics, men with too much dark power, with the help of the newly founded Noble Church that, in the rising age of Azoth (the legacy of the gods), cemented the new nobility's rule.

Azoth:
This ore can be found across the world and its origins stem from the war against the Gods. Historians point to the singular event that both defined and ended the war - the creation of the Godfall - as the actual cause of the creation Azoth in the world. The destruction of a god who sought to consume the very sun in the sky laid waste to an entire country causing it to become the wasteland that remains the most Azoth-rich region known to exist.
Azoth has become contentious: its use is so pervasive and intertwined with society that it cannot be undone. However its side effects are becoming more wide spread. It is no longer contested that the condition of physical mutation known as the Burn is directly linked to the energy that Azoth spreads in the world. Weaponised forms of the ore have been outlawed through the Azothic convetion recently.

The Quorum:
At the height of their power, prior to the war, the gods that men became, created a realm of their own. Away from the world they could discuss their affairs, conduct research and otehrwise indulge their powers and whims. Soon they took lesser mortals as servants, chosen from among the faithful (or pressganged as slaves, the difference was not a matter for heightened minds), to serve within. Such mortals required 'alteration' in order to properly serve and survive within this magical plane; they would never return.
With the coming of the war the Quorum became a battlefield and those mortal servants forced onto its frontlines. The desctruction wrought in this peculiar environment was all the more unpleasant and the Quorum was forever left a haunted place. With the gods no more only those mortals twisted by the power of their former masters remained. They took the place as their own with no other home to call their own, and thus the eponymous people of the Quorum became their own race, a mutant offshoot of mortal man. The modern world is as alien to them as the world they once called home; indeed for almost all they have never seen their ancestral birthplace.

The Burn:
Due to the influence of Azoth there exists a condition in certain people that leads to an inability to harmonise and process the energies now present in the world. This condition is called the Burn. Without intervention, the individual finds these energies growing in intensity; the pressure builds until they must find a release. This release is devastating and uncontrolled. In most cases the individual is destroyed in a literal explosion of energy. In some the individual can survive - though only temporarily.
The only way for an individual showing signs of the Burn is to wear a Burnsuit. This is a bodysuit that grounds the individual, so to speak, allowing them to function without risk to the environment (and themselves). Burnsuits were first created by the Numinous Institute. Such is the danger that society faces from the Burn that those who suffer it are ostensibly the property of the Institute and must succumb to the wearing of the suit.
In return for living under the Institute's auspices, the individual is trained in how to make use of the energies within them allowing them to call on unique abilities. They are also given a place to live and food to eat as well as something of a purpose in life as the Institute believes those abilties are to be tapped for the betterment of society. Consequently agents of the Institute find work throughout the Empire, for which the Institute is handsomely rewarded allowing them to continue their unequalled research into the effects of Azothic mutation and the Burn.

The Darkling League:
A group of so-called Institute outcasts and Burn sufferers who reject the orthodoxy; they believe they have mastered the condition without the need for external help. They resent the Institute (and society) for hamstringing the natural evolution of the mortal form. They are charismatic, but violent. Their views firmly place their kind as discintly separate and superior to those who do not suffer the Burn. Consequently they push, violently, for their perceived place in the social order and believe that it will come inevitably.

The Genestone:
With the help of Azoth the Genestone was created as the source for the cure for an incredible number of diseases and conditions. However it remains in the hands of those who would rather profit from it than see its, admittedly expensive, use more liberally applied. It remains one of the most powerful of all the breakthroughs Azoth has enabled. The Genestone is located in the bowels of the Imperial Surgical Forum and access is heavily monitored and guarded.

The Deathless Mask:
A cult of doctors who have manipulated the use of the Genestone to further the improvement of the mortal condition. They seek to use Azoth as a cure for aging and offer the results of their often grotesque research to any who can fund their continued efforts, welcoming patrons with the lure of immortality. The Mask operates within the very halls of the Imperial Sugical Forum; members are secretive and clever and have direct access to the Genestone to further their highly illegal research. Though immortaltiy remains beyond their grasp - for now - they have achieved a number of macabre and potent results, allowing individuals to wield powers, though unstable, akin to Institute agents. The Empire has branded this use of the Genestone as punishable by death.

Burnsuit:
...Now here is where I get stuck: what does a Burnsuit look like? Does it even appear as a conventional outfit? It needs to be something that works as a tool for roleplay, otherwise what's the point of having the Burn involved at all. It can't therefore be infallible or random, or too limiting. It separates those with the Burn from everyone else, so it needs to be imposing.

Thanks for reading.