The infinite cosmic soup in which the planes of existence supposedly reside. No one is quite sure how to define it as it's explanation defies intelligible vernacular, but there are some prevailing theories. Some believe that the planar sea is defined by the absence of existence, it is the zero point of existence, defined only to make reality make sense. Some believe that that within nonexistence is a different form of existence that transcends the dimensions we understand, that the absence of energy is an energy in and of itself.