A Complete Guide to the Cosmos - Prime Planes
by Giulio CarolettiThe Prime Material Planes have a special importance and meaning in the Multiverse and its cosmic struggles. For the first thing, Prime Material Planes are among the most accessible ones from other planes. They are dotted with gates and vortexes, that lead to and from outer planes, inner planes, other prime planes; thus, Prime Material Planes are important "railway stations" or "airports" for every planar creature that wants to travel anywhere in the Multiverse. For the second thing, the Prime Material Planes bear a unique feature in the Multiverse: they are the Planes of Belief. Belief can make mortals Immortal. Each Prime Plane has a different way of displaying this feature, but it is nonetheless the same: through belief in themselves, a strong group of followers, and the performing of impossible quests, mortals can become Immortals.
At this point, you could wonder why I am speaking of Prime Material PLANES instead of a single Prime Material Plane. It is simple. I am speaking of Prime Material Planes, because there are several Prime Material Planes, and not only one. The planar position of a single Prime Material Plane is known to every planar creature and god. A Prime Material Plane is surrounded by the Ethereal, and through gates that pass through the Ethereal itself it is connected to the four Elemental Planes (and to the quasi- and demi- elemental planes). Moreover, planars, gods, prime adventurers believe that the Ethereal is also filled with pocket-planes and demi-planes. The problem is that THEY ARE WRONG. The truth is that most of this so-called "demiplanes" are the other Prime Material Planes! Feature Three of the Prime Material Planes, thus, is that they ALL share the same Ethereal and the same Elemental Planes!
But there is still one more important thing to note: each Prime Material Plane has its own Outer Planes and its own Gods. It's impossible from one Material Plane to reach an Outer Plane that belongs to the Multiverse of another Material Plane!