Aeterno: Planar Rift
The Elemental Planes have lost their pure elemental force, bleeding into one another and the Material Plane and causing great discomfort for some of the more elementally-attuned races and creeds. These four Planes of force have effectively fused with one another, forming the Elemental Ringworld and remain separate from Aeterno ’s soil, needing a spell or standing Rift to pass into.
The second half comprising the Innersphere, the Other is made up of all the Planes that lie congruous with The Material Plane and retain similar features. These Planes are the Shadow Plane, Ghost Plane and Positive- and Negative- energy planes. Their adhesion really means that they can be passed into with very low-level spells and in tumultuous areas can and will open without warning, trapping travellers between filters of reality.
The Outersphere is made up of the 9 Overworlds that lie on the outside of the Innersphere. These 9 represent the complex goals and desires of the peoples that inhabit the The Material Plane. The worlds themselves serve as final resting place for souls who perish within the Innersphere and they lie in strata, the Plane of Good and Plane of Evil lie opposite eachother, stretching out to infinity across what each views as their sky and earth. Split into Chaotic, Neutral and Lawful, the borders arc away from the centre of their Plane, where each meets the ends of the Elemental Ringworld , out into the darkness. The Neutral Strata hangs in the space between the highest peaks of Hell and the misty clouds of heaven, the three Planes rotate around the Innersphere and invisibly fill all the space between the Good and Evil Planes.
Stranger still is how the Positive Energy Plane and Negative Energy Plane came to be fired out of the Innersphere, stretching themselves and dragging the Elemental Ringworld out past the good and evil planes, decimating all that is good and evil in their home planes. The congruous Positive and Negative energy Planes now serve as the easiest way for People of The Material Plane to slip onto the Planes of Good, but because of the nature of those Planes, Angels, Azatas and Agathions cannot pass through the negative plane and Devils, Daemons and Demons cannot pass through the positive, the only effective border to be found anywhere in the Multiverse.
Other stranger lands lie in the Astral Plane, the gaps between all these flowing areas, entire universes that flow through spacetime, oft coming into contact with the Outersphere and rarely, if ever, falling through the boundaries and winding up within the Innersphere. These spaces are infinite in size and number, and can have a portal opened in nearly any location. Travel within them is possible, if infuriating: there is very little control over where you may end up. More often than not, the nature of the idealistic Outersphere causes travellers to end up in the very last location they’re looking for, or staring into the face of a deity they’ve been thwarting recently.