User blog comment:Onic14/Nature of the Slayers/@comment-24934658-20140728223848/@comment-24800928-20140729015952

my theory on God Slayer Magic was that it was never able to reach its full potential because it hasn't been taught by The Gods Themselves (Isaac Asimov :P). The Gods may have had more of an impact/influence on humans, and could have tought their magic at some point. Then they realized that they and their magic was to strong. Against stupidity the gods themselves contend in vain (hehe another reference there), so they completely left the human realm to prevent a catastrophe or any further touble, but left a little piece of their history by leaving behind their magic in books, knowing that a human could never reach the magics full potential with being taught by a god.