forbidden place

A long long time ago, there is an empire, it is full of strength, a lot of powerful creatures, elves living in this place. They have been living in the Millennium.
They have God living in the empire. He had three of his forehead, his powerful, cruel and crazy. The empire has its own culture, language and knowledge. They go to war. God wants to conquer the world.
After five hundred years of the war years, he lost the war, he was sealed in a cave. And start on that day this cave as a forbidden place. But one day, they will come back and release it.