Mu was a continent that was located in the Pacific Ocean. Indonesia and Japan were once part of the Muan continental mass. From about 10500 BC, Mu was ruled by the cult of Az-Ath-Oth. This government called itself the Theocracy of Mu and was formed by exiles from Atlantis.

The Theocracy went to war with Atlantis in about 10300 BC. The war was waged for 300 years or so, until both sides discovered the ritual for time-travel. The First Time War was fought between 13000 and 9000 BC, but ended with both continents sinking into the oceans at about 10000 BC, resulting in the final destruction of both cultures.

The Children of Dagon were the only survivors, fleeing into the future to escape the cataclysm.