After God slaughtered and consumed another alicorn, revealing himself to be a cannibal, the Goddess banished him and all memory of him, locking it all away in his own mind. God was deemed a failure as he was completely sterile and unable to breed with the other alicorns.
God was an experiment of The Goddess, an attempt to create a male alicorn to help perpetuate and preserve the alicorn race, outside of converting other ponies.
