[Authority of the Undefined God]
"Uncanny Valley."
In the ancient history of humanity, this pertains to the phenomenon of encountering 'something' almost, but not quite human. It is something familiar yet strange, leading to discomfort, an eerie or unsettling sensation that even develops into 'fear' of the unknown, the oldest emotion of humankind.
This was its 'meaning' in the modern world of the now-ruined world called Earth.
In this World of Magica, however, though it was closely similar, it's an 'authority' of the mysterious entity only known as the [Undefined God] that allows its possessor to become something that's not of this dimension; something that the person might know but would not want to know.
Just as the peculiarly structured saying goes:
"Gods fear what cannot understand."
What more if they are not a god?
