There is an imbalance in a village in the Outlands where the Inner Planes and the Outer Planes meet in a kind of mess, like when saltwater and fresh-water meet in a brackish swamp but instead of water it is ideas and rather than mud you get raw elements charged with ancient passions.
- Lightning, Air and/or Vacuum
- Steam, Water and/or Salt
- Mineral, Dust and/or Earth
- Radiance, Fire and/or Ash
- Balance, True Neutrality
- Alien Far Realms
- Blood War spill-over
- Prime Material yokel nonsense
- Tides of the Astral Sea
- Reflective Glare from the Mirror Plane
- Demi-Plane of Dread Creepiness
- Realm of Dreams
- Big city interference from the hub
- Shadow Realms Obfuscation
These are the planes where elements and philosophy crash into one another causing alien landscapes to be born. Magma growing solid might be the cooling of an ancient feud. Salt might be preserving ideas that were better abandoned and decayed.
7, 2, 4
Radiance, Fire and/or Ash, Good, Mirror Plane
In the lovely village of Iggen every fire in the town has become a portal into the mirror plane, showing people their greatest good deeds. Some folk are walking into these fire, catching aflame and also destroying that moment in the past when they did good. People’s memories are becoming infested with fiery reflections of those who offered them kindness, screaming from the fire they walked through to get there.
4, 7, 3
Ooze, Balance, Tides of the Astral Sea
Usawa is a swamp-town in the middle of nowhere, poised on the edge of the Astral Sea but without a deep enough body of water to be a port without serious arcane-industrial dredging that none are willing to do. Lately, pieces of an ancient religion dedicated to a dead True Neutral Druid-Deity have been washing ashore in a state of perfect balance. When these ancient wrought-iron tools are exposed to any act of good, evil, law or chaos they become dangerous cursed, turning their wielder into agents of an ancient hunting pack designed to keep balance in a newborn universe.
Brushed up on the planes with this wikipedia article, Plane (Dungeons & Dragons)