Four Empires is a total conversion modification for Warcraft III: The Frozen Throne that turns the four vanilla races into different ones. The Universe in which the mod takes places is one of my own imagining and has nothing to do with the Warcraft universe.
The Holy Empire is the replacement of the Humans, a theocratic empire that rose to prominence after their god-like Emperor clawed his way out of Hell to guide humanity into an age of enlightenment.