Ethereal plane

It is a plane out of phase.
It is a place of ghosts and monsters.
It is right next to you, and you don't even see it.

 

A mirror of our world

The Ethereal touched the Prime at all points that were located within crystal spheres through what was called the Border Ethereal. It was unknown whether the Border Ethereal touched the Prime before the dimensonal shift.
    The non-Border region was called the Deep Ethereal. While in the Border Ethereal, a traveler could still see into the adjacent plane but only dimly and not very far, whereas those on the bordering plane could not see the traveler without magical detection. Verbal communication was not possible between the Border Ethereal and the bordered plane. The Ethereal was unique among the many planes in that an individual could exist in two planes simultaneously: the Border Ethereal and the adjacent plane.  

Travel

When a traveler crossed into the Border Ethereal, she and all her possessions were converted to their Ethereal equivalents, metal became ethereal metal, flesh became ethereal flesh and so on, allowing free movement (in most cases) in any direction through the solid matter of the adjacent plane. Since everything was permeated with ethereality, an air-breathing creature could breathe ethereal air and could not drown in an ethereal lake nor be crushed by an ethereal rock. However, not all in the adjacent plane was insubstantial. Living things larger than one-celled animals generated an aura that radiated around them and prevented passage to their interior, so an ethereal traveler could not place a weapon inside a living creature where it would materialize and cause damage.