12.15.1 Planes

Achaea exists on the Prime Material Plane. The prime material plane is one of
many planes of existence. Known planes include the Underworld, Chaos, Nirvana,
the Parthren Gare, Annwyn, the Inferno, and Nishnatoba, among others.

The planes' connections are tenuous, resulting in occasionally restricted
communications and/or movement.

There exist a few locations in the multiverse so inherently dangerous that they
have earned the designation of "Treacherous Plane." Simply being on one of
these planes puts you at risk of being attacked by anyone, for any reason - or
no reason at all. Once you leave the lawlessness of those planes, you may not
seek retribution for what happened there. The following planes fall into this
category:
- The Underworld
- Annwyn
- Nishnatoba
- The Underrealm (while not strictly a plane, the treacherous designation applies beyond its barriers.)