Cthulhu slept in the city of R'lyeh, a sea city in the South Pacific, but due to the influence of the cosmic aspect or other external factors, sometimes the city of R'lyeh would unseal the seal and appear on the sea. However, because the seal was not completely unlocked (maybe to wait for the family members to wake up), Cthulhu could not stay away from R'lyeh. Later, when the horoscope changed and the power of the seal was restored, he would return to R'lyeh and continue to sleep.