The Sea of Time

This area of the ocean is guarded by Poseidon and acts as a maritime minefield of rapid currents that could tear smaller ships apart and dash larger ships against the rocky reefs surrounding the area. The reefs themselves were created by underwater volcanic activity, with the upper tips of a few volcanoes breaching the surface of the water even. The area is surrounded by a perpetual fog that makes sight difficult, but it's rumored that an Atlantis-esque ancient society named Lemuria hides deep within. Some speculate that this is the same ancient kingdom rumored to lay on the ocean floor in the area, while others insist that they observed the hylian royal crest, rather than any Lemurian symbols.