The "world" of Wyrmstone is in fact several individual worlds, each with its own peoples, problems, and perils. Travel between each is performed using Wyrmstone-powered Highsailing craft that open gates to cross the vast distances. The jungle world Issara is encountered first when travelling from the Hearth outward. Then comes the water world Ra'niah followed by the desert world Daigon. Beyond Daigon lies the forest world Liunonda, the scattered blasted remains of the Nar world known as The Web, and the enigmatic world Shahan. All but Shahan circle The Hearth, a great and revered sphere of holy flame. Beyond Shahan lie the forgotten and hidden worlds of the Hollow, long lost to modern civilizations.
All of the worlds exist within the Void which is the vast empty distances between worlds. The Void has air, though it is extremely thin--much like being on top of a high mountain peak. Most creatures cannot survive the thin air for long. Further, because of the vast distances it would take centuries to travel between worlds, which is why travel between worlds was limited to the arcane until the discovery of the Wyrmstones.
High in the clouds around all words float the aether chains, monolithic islands suspended by primal forces when the worlds were created. Aether islands come in a wide variety of sizes and concentrations. The upper side of the islands are usually flush with life and towns have been established on some, though trade to the surface is expensive.
Beyond the clouds of some worlds are one or more moons. These are independent spheres like the world itself, larger and more independent than an aether island but circling the parent world, not the Hearth.