The question, where did sanctuary energy come from? Was a question that has always been, God's have asked this question and so have mortals.
Even creatures with low intelligence eventually asked themselves that question, eventually they made up a tale that goes like this;
Before reality came to be, there was simply nothing, there was no flow of time, no branches , no universes, no realms, no dimensions. It was empty in all sense of the word.
Although in all essence this place was empty, five beings lived in this nothingness, four of them armed hands against one, and in their attempt, all five died.
In the place of their death, five orbs of infinite energy were formed; these orbs were so powerful and infinite in energy that they formed all that exists now, they are the energy that keeps reality itself alive.
They say these orbs are the origin of all energy, the energy that even The Gods who stand above all reality use to maintain themselves. "
Although that is how the tale goes, no one knows if this is true.