The Fourth World is a fictional setting by Jonathan Rivalland.
Of all the known worlds, of all their nations and all their peoples, there is little rarer than the Helions. Each of these ancient structures is a vast, freestanding portal to other worlds; made by an unknown hand long before humanity arose. Those who control one can claim vast wealth by means of trade and movement through these portals. And on the world of Brisia, it is controlled by the nation of Reimar.