In the beginning, there was only Olorun and Olokun. Olokun was the origin of Yemayá. For a long time Olorun and Olokun fought for dominion of Earth. Whenever Olorun sent something to the Earth, Olokun took control of it. Olorun wanted to reign everywhere and Olokun, in order to demonstrate his power to him, caused the sea to raise. It was necessary to cool Olokun so that the Earth returned to existence. So terrible and powerful is Olokun that when Olorun separated from him he went to up to the highest point and Olokun remain beneath. It was then when Obatalá had to tie him up with 7 chains because, when he saw that people were neglecting their worship, Olokun wanted to drown to the whole of humanity including all the animals. Olokun lives at the bottom of the ocean, next to a great marine serpent that shows its head when there is New Moon.
Some believe that he is half man, half fish. Still anchored down as he is, with 7 chains, whenever he is enraged, he causes great damage, and for that reason Obatalá was very prudent in leaving him moored so that men would not forget their worship.
Olokun was amphibious, and for this reason did not want to have relations with his great love, Orisha-Oko, in order not to be the object of ridicule. He asked for the advice of Olofi whom a assured him that Orisha-Oko was a serious and reserved man. Olokun took confidence and it went away to live with the orisha farmer, but he saw that he had birth defects in his nature and he told it to the world. The shame caused Olokun to hide in the bottom of the ocean, where everything could be ignored and where nobody would be able to reach him. Others say that he became a siren or a great marine serpent. But nobody knows if that is so