Empyreans is a dark fantasy setting in a post apocalyptic world. A cataclysmic world war tore a rift in the planet, and from it a strange energy began to seep forth. Everything this energy touched distorted: technology rendered useless, animals warped into monsters, and plantlife into poisons. A spare few reacted favourably to the energy, developing evolutions that enabled them to focus the energy into magic, alchemical applications, and artificial animation of ore. However, as they used more magic, they became sterile. To propagate their fledgling species, they'd need to find survivors and infuse them at a young age. 

So they built Empyrean City, the last bastion of culture and civility in a ravaged world. There, they infused their foundling youths with one of four types of energy: Choleric, Phlegmatic, Melancholic, or Sanguine. Each youth is trained to use magic to fight back the monsters that prowl outside the walls, seeking a way in. As the magic gradually changes their bodies, they gain access to the hidden secrets of the city. Only by reaching the peak of Empyrean society will they finally learn the dark truths about their origins, the World Rift, and the very city's founding.