planar keystone

Note that keystone is an umbrella term - these need not be made of stone.

These unusual features manifest on the material plane as a connection to another plane, usually allowing some flow of power between the two. This allows for impressive exercises of the energy plentiful on the other plane and may even allow travel between planes.
Suspected examples:

• The War-Forges of Threkt are reputed to connect to the Elemental Plane of Fire
• The mortispire in Estimarth

Item type

Magical