the inside-outer planes

Never let it be said that the cosmos lacks a sense of justice: it wants to balance the scales of a great many things exactly equal. e must equal mc2. PV must balance nRT. A ship's displacement is its weight. A refrigerator must create heat exhaust. An action has an equal and opposite reaction, and a concentration of good souls must be balanced by an evil environment, and visa-versa.

Prophets, priests, and public schoolteachers little like to acknowledge this fact. Doesn't the cosmos know that people respond to incentives? No, it does not. It does not know anything. It just plugs along with a sense of harmony generally better appreciated by architects than apologues. 

Foredurance is the abode of the saints. They are assailed by tropical diseases, frost, plagues of frogs, cluster outbreaks of lycanthropy, humidity. However, the victims of Foredurance are a naturally cooperative lot, and have made a community in the midst of the abbatoir.

When the Outsiders native to Foredurance make their way to the prime material plane, they tend to go about finding people they admire and making life hard for them to prove a very important if rather obscure point. The Book of Job almost certainly records such a breach, aside from the Hollywood ending at the end, which was almost certainly added by marketers.

Emmurdegris is the reward of the damned. Near its center, the multiverses' most evil souls are so blessed that they cannot feel pain, and thus must come up with truly ingenious ways of torturing each other. Across its suburbs, a temperate, fructiferous paradise of rolling hills, mere jerks mostly play lonesome pioneer on their own little plot of land, congregating every so often to play social status games. 

When the Outsiders native to Emmurdegris make their way to the prime material plane, they take manifold blessings and bestow them on someone who absolutely, positively will not get any use out of them. Some of these people are bound to go to Emmurdegris themselves, but others are just idiots.

Dunnore is a featureless, unchanging Pamenidean sphere. Its inhabitants can’t so much as throw graffiti on the walls. But some have figured out ways to communicate with each other, however subtly, and beneath the monochrome surface hyphae-like networks teem as new artistic movements are proposed and abandoned.

When outsiders native to Dunnore visit the prime material plane, they preside over not Interesting Times but grace people with the calm to do something interesting: whether that take the form of imprisonment, prosperity, convalescing a broken leg, or whole decadent ages which can reap the fruits of Autumn. It is said that they are present, too, for the fashioning of worlds; for their having laws that will inspire artistic reflection or scientific speculation.

Cataplysis is Dunnore’s cardinal opposite: a riot of unpredictable stimulation and changing physical principles. Its inhabitants make the best of it that they can: like the Foredurants, they are a naturally cooperative lot, though their form of cooperation depends more on formal structures and a heavy application of those incentives the cosmos likes to ignore. It is said that Cataplysis has a sense of humor, but that its jokes are always just beyond or below what the inhabitants would recognize as such. Near the center it is downright hilarious.

Native Cataplysts come to the prime to provide the soupçon of chaos that provoked the higher order. Species evolve, fetters on the forces of production are superseded, buildings stand or totter on the strength of their design. These anarchons are among the least discriminating of encroachments - they assume that any unanticipated threat or opportunity will most benefit the highly structured.

These are just the cardinal directions - or some of them; the inside-outer planes may have more than two dimensions. Further planes, their guests, and their hosts are left as an exercise for the reader. After all, you should know what's in store for you.