Requiem

Requiem is a universe in the multiverse. Requiem is a drab and grey world with a history of constant warfare and no art or music of any kind. The endless war was finally ended by a major cataclysm which destroyed Requiem's sun and drove all of the fantastical humanoid races (elves, dwarves, gnomes, etc.) to extinction. The remaining humans struggle to survive in a haunted world plagued by ghosts and terrifying demons.

History
When Requiem was created, its gods didn't get along. Instead, they fell into petty squabbling over how the world should be created and run, separating into three factions. This squabbling soon erupted into all-out war between the factions, and the mortal races were created with this in mind, as pawns and foot soldiers in their ongoing divine war. One faction created the Imperium, an army of humans who forge arms, armor, and war machines from metal. A second faction created the Hadrathi, a diverse collection of fantastical humanoids such as elves, dwarves, and gnomes, who honed their magical power to cast spells, craft artifacts, and summon elemental forces. The third faction created Tycheros, a nation of fiendish tieflings and beast hybrids with dark, shadowy powers tied to the lower planes and the Gates of Death.

These three armies were locked in an endless war for millennia until the year of the Cataclysm. The Hadrathi had consolidated their power and slowly began gaining the upper hand against their enemies, and the Imperium was desperate. An ambitious human worked together with a Tycherosi named Kotar to blow up the sun in a massive explosion that obliterated the entire Hadrathi population and shattered the Imperium into a collection of disconnected islands. In the aftermath, however, the world was overrun by demons, and it became clear that the human had been tricked by Kotar -- Requiem's sun was actually the Gates of Death, a sealed portal to the lower planes, and by destroying it he had inadvertently released full-blooded demons into the world. Furthermore, the souls of the dead were no longer bound to the lower planes and remained on the world plane to haunt the living.

The endless war forgotten, the humans scrambled to protect themselves and their cities from being overrun by demons and ghosts. Through the invention of lightning barriers, powered by the blood of slain demons, they were able to mark out sanctuaries for the survivors and begin to rebuild their society. The human who helped cause the Cataclysm, having been granted immortality through the deal with Kotar, became the Immortal Emperor and spent the next eight hundred years working to reunite the Imperium and return it to its former glory.