Manual of the Planes

Planar RelationshipsPlaneAPlane ACoexistent Planes(planes in directoverlapping, point-topoint contact)PlaneBCHAPTER 2:CONNECTINGTHE PLANESPlane APlane BSeparate Planes(planes not indirect contact)Plane BCoterminous Planes(planes in direct, butnot overlapping or inpoint-to-pointcontact)deities that are unreachable or that don’t have extraplanarkingdoms. You can determine that fiendish and celestialcreatures come from the same plane, or that all elementalscome from the same swirling maelstrom. And you maydetermine that you don’t want to have any of the TransitivePlanes in your campaign.Your cosmology can reflect your own desires for yourcampaign. If you want to stress the struggle betweengood and evil, then setting up strongly aligned planes forthese concepts is an excellent idea. Similarly, if you wanta strong conflict between organization and freedom,strongly law-aligned and strongly chaos-aligned planesare recommended. You can create, add, and subtractplanes as you see fit. If you want a fifth elemental plane(perhaps elemental cold, elemental wood, or even elementalemptiness), you can do so within your cosmology.DECIDE WHICH PLANES YOU WANTYou have a great degree of freedom when you build yourown cosmology. You can add new planes, alter others, andsubtract the ones you don’t like. Among the five basictypes of planes, here are your options:Material Plane: This is a good foundation and agreat place to start. Unless you are crafting a cosmologythat exists far beyond the norm (which is exciting byitself ), the Material Plane provides the home for yourplayer characters. Players have basic assumptions abouthow things work, and a Material Plane base lets themuse that knowledge.Wildly different Material Planes are possible, anddesigning one is a good challenge for experiencedDungeon Masters. After all, many planar traits comparean aspect of a plane to how it works on the MaterialPlane, so if you change the Material Plane, you’rechanging the baseline of the whole cosmology. Ifthings are radically different on the Material Plane youcreate, the characters probably are aware of their homeplane’s properties. For example, if anyone can reach theAbyss by taking a three-day walk to the west after a fullmoon, the natives of this unfortunate Material Planewill probably know about it.Transitive Planes: Many spells, items, and monstersin the D&D core rulebooks depend on the Astral Plane,the Ethereal Plane, or the Plane of Shadow. Removingany of these planes affects what’s available in your campaign.Chapter 5 details what happens to your campaignif one or more of the Transitive Planes don’t exist.Conversely, you may want to add another TransitivePlane to those that are already available, such as the Planeof Mirrors (detailed in the Appendix). This can open thedoors to further adventures, new creatures, and spells.Inner Planes: These are the building blocks of yourcosmology. Elements and energies are pure substances,deadly and uncaring to the mortals that encounter them.The Inner Planes can be most hostile of all the planes.Despite their fundamental nature, they aren’t required inyour cosmology. The lack of an Elemental Plane of Air doesnot remove air from your Material Plane; the characters17