Is universe C the same as the universe that is built? Or is it just the universe all the kids build's earth that becomes the home of calliborne and calliopie after it travels through a black hole?

Universe C is the universe created by the kids’ session. They also took B2 Earth to Universe C which eventually became home to the Cali twins. The Earth doesn’t go through a Black Hole until Caliborn starts his session and it just goes to his medium.