Cthulhu is a monstrous entity who lies in the city of R'lyeh sunken below the depths of the Pacific Ocean. Memory preserves him as humanity's most basic nightmare. Cthulhu appears in various monstrous and demonic forms in early myths of the human race. Cthulhu is the high priest of the Great Old Ones, unnatural alien beings who ruled the Earth before humanity formed. It is said that they will return, causing worldwide insanity and mindless violence before finally displacing humanity forever.