Birth by Sleep Kingdom hearts overall theory

I had this weird theory about the secret ending, well at the end of the secret ending Xehanort is holding this pulsating magic in his hand that shoots up remember. After that Kingdom Hearts appears in the sky, what if that magic created it, the one thing is, what magic was it?

I think it might have been Vens heart or something.
(Highly Unlikely, then he would be dead or a heartless.)