Wild Blue Yonder

Physical realm of remnants and most life, third from the top in the planar stack

The predominant space of life as reality defines it in the Heavens: in effect, the Material Plane in standard D&D terminology. Bordered by a layer of thick cloud above and below it, the great skies house huge floating landmasses called remnants populated and conquered by humanoids, flora, and fauna. These landmasses spread out across vast stretches of open, blue air called oceans, or “skyseas”.
It is said that the Wild Blue is the plane closest tied to psychospace.
The air is normal, but changes pressure depending on distance from a landmass or the current weather. Creatures who can flap freely through the Yonder’s high-pressure skies are said to be aeronautic, capable of swimming through thin air.
Throughout it swim a consistent flow of clouds, formed of precipitation and other materials from the plane which borders it overhead, the Above. These clouds occasionally harbor life all their own.
Airships are most often found in this plane, constructed by the societies as a manner of approaching diplomacy across remnants. These act as aeronautic vessels for those who cannot fly, and are propelled by a number of magical technologies.
Below the Wild Blue Yonder is a thicker layer of clouds called the Xibalpause which leads to the Scarlet Skies.
Within the planar stack, the Wild Blue is third: below the Above and atop the Scarlet Skies.

The terms "Material Plane" or "the open sky" can be considered interchangeable with the Wild Blue Yonder.

Type

Dimensional plane