Ethereal Plane

The Ethereal Plane is a veil of foggy overlay that exists across the surfaces of the Material Plane, the Feywild, the Underdark, and the Shadowfell. It is a common destination of interdimensional travel, particularly for wizards and other arcanists who wish to avoid detection by normal means.
The Ethereal Plane is divided into two layers: the Border Ethereal and the Deep Ethereal. The Border Ethereal is the most easily accessed by arcane means; from within its bounds, a planar traveler can see their immediate surroundings in the plane they recently left, though they are surrounded by a lavender haze, which they cannot see more than 30 feet through. To those in their original plane, travelers on the Border Ethereal are invisible, incorporeal, and utterly silent. This makes the Ethereal Plane ideal for avoiding attacks and conducting reconnaissance missions.
The Deep Ethereal, by contrast, is much more difficult to reach and to navigate. One must access it via the plane shift spell; even then, its circles are a closely-guarded secret of diviners. The Deep Ethereal is a land of constant rolling mists, through which occasional glimpses to other planes of existence may be seen. Planewalkers wander through it in a dreamlike state; distance is meaningless, and time is impossible to track. Translucent, fluttering curtains around the Deep Ethereal conceal windows into other planes, both those adjacent to the Ethereal Plane and those situated beyond the Beyond.

Type

Dimensional plane