Planar coterminalities, also known as planar tears or less accurately as planar portals, are locations in which the borders between planes are particularly thin. In these areas, energies, objects, and even creatures from one plane can easily transit into another.
Description
Coterminalities are frequently highly visible, with noticeable differences from the surrounding landscape. Permanently scorched ground cover may mark a coterminality to the Plane of Fire, while those venturing into a coterminality with the Negative Energy Plane may have their life slowly drained from them. Not all coterminalities are so hostile, however. First World coterminalities, for example, can regularly be located by searching for plants of bright and unusual colors, or shimmering and glowing water and air.
On occasion, creatures from one plane can use a coterminality to travel to another without the use of Planar Shift. This process is highly unpredictable and usually accidental.
Examples
The Warps are a type of planar coterminality.
The Untamable Lands near Rudamun are the site of a large scale coterminality with the First World.