Material Worlds: These worlds are a lot like most campaign settings: lands divided by mountains and rivers and bounded by oceans, forests of trees, and kingdoms filled with cities, towns, roads, and farms. In some ways, viewed from a metagame perspective, an material world might seem like somebody else’s campaign world. Not all material worlds are that big or robust, however.
Parallel Worlds: Dimensional travelers can sometimes find their way to a world that seems exactly like their own. However, the experience proves to be extremely disconcerting when differences ranging from the almost imperceptible to the wildly catastrophic show it to be an entirely different world—a parallel world. Parallel worlds exist because certain types of planes simply seem more likely than others. No one
knows exactly what makes a type of world more common than others. (It should be noted that many alternate worlds, as described above, also have their own parallel worlds.) In any event, parallel worlds exist with similar or identical geographies, places, creatures, and even individuals.
Heavens and Hells: There is not one heaven and one hell, but many—perhaps endless numbers of both, each individualized and separate, none forming anything resembling a cohesive whole. No lord of heaven is master of all celestials and champions of goodness, and no duke of hell rules all demons and devils. Instead, many such beings thrive, including demon princes, archdevils, angelic kings, and celestial stewards. Each rules an appropriate world (or, rarely, a portion of a world , or even more rarely, several worlds at once).
- Using Heavens. Planes referred to as “heavens” are normally peaceful places, well ordered and safe. These are usually homes to angels, celestial beings, and good-aligned deities. The PCs can travel to heavens on missions to find allies, advice, or magical aid.
- Using Hells. As one would expect, hells are awful places to visit—horrific realms with deadly environments and natives who are sadistic, maniacal, and bloodthirsty. Hells are usually homes to demons, devils, hell hounds, fiendish monsters, and far worse.
Energy/Elemental Worlds: Some worlds are pure energy, or nearly so. Worlds of pure magical energy exist, as do planes of only positive energy or only negative energy. Other planes are composed of a single element, or primarily of a single element, so much so that they are identified only for that element. These planes are usually the home of elemental beings, from elementals themselves to genies, xorns,
and far stranger creatures. It is believed that all worlds of a single element or energy type are connected, while those elemental worlds located in the Inner Planes can be travelled between physically.