The Ethereal Plane was once a realm of lightness and celestial brightness, but it was Lost in an ancient universal war. The essence of it was scattered throughout many different realms. It takes on different forms and different properties in different realms and even in different circumstances, but on Shem, it is a connective energy that bonds literally anything together. Controlling it requires bonding directly to the energy itself:

Ethereal Bonding

Bondsmage