Major Planes

The major planes are those with the densest populations and are where the vast majority of Crossover's citizens hail from.

Minor Planes

The minor planes are still large enough to be named but are sparsely populated in comparison to the major planes. Some minor planes are closer to "major" status than others.

Other Planes

Truly, there are a significant number of planes around the base planet, but not all of them are easily habitable or accessible. While trickles of people come from planes other than the named ones, they're few and far between, as most other planes are insular and prefer it that way. Unnamed planes have some of the most peculiar location-specific will abilities, but since the other planes aren't extensively catalogued, only the inhabitants of an other plane will be able to tell anyone what they might be.

Plane Structure

The planes are arranged in a shell structure over the base planet, existing in dimensions that "blend" with its neighbors to varying degrees. The center planes of the shell interweave tightly, with many points of overlap that makes travel between them fairly painless (and sometimes unintended). However, the farther from the core you travel, the harder a plane is to access. Most of the inner planes are just fine with that arrangement, since the vast majority of the outer planes are demonic in nature and hostile, both to outsiders and amongst themselves. The one major exception is the Kingdom of Heaven, the outermost plane, where access is damn near impossible and the angels work hard to keep it that way.

Crossover's existence is a paradox, since it seems to occupy both every plane and no plane at all. Its shape is the subject of much debate, though the current consensus is that Crossover serves as the central "pillar" that anchors the other planes around the base planet.