Ethereal plane

Like a blanket over the world it is the place where the life energy actually flows. In this plane you can see the flow of life energy.
A plane of the color of life energy, the denser life energy is at a point the more vibrant and glowing it is, the less it becomes gray and muted, most places are more on the gray end. All of it kind of looks like a constant mist slightly flowing, nothing is solid, all is see through(though if it's very bright it might be difficult) and no physical matter naturally exists in the plane(only that which is teleported in.)

This plane is also the plane upon which you can see and interact with Souls. They are near tangible here and you can see the souls of those both living and dead here moving around (though dead one's are quickly taken to a afterlife with a few exceptions)
Things that move into the plane can use it to manuever around ecpecially if they can move between the planes quite easily.