The world is divided into spheres, areas of vastly different life, topography and climate, separate by a dense barrier called the Mist. Each sphere is granted life through one or more world hearts, crystalline orbs filled with divine power that generates the heat and light. Travel between spheres is only possible with navigators, people who either through the grace of the gods, fine-tuned magical senses or other mystic ways can allow people to travel through the Mist to other spheres.
Each sphere as its own cultures, its own people and its own problems. And thus also its own opportunitets for adventure, heroism and villainy.