Naiads are so much unlike Ongs, that people of Aelion were for a long time certain that these two are different kinds, united under the rule of one great god. Many years have passed, when immortal Protheus, who was charmed by the underwater world and studied Oceanids carefully, proved that Naiads and Ongs are female and male creatures of one kind, separated by ways of the evolution.
Later he discovered, that their spiritual ways went in different directions, too. Naiads are more bloodthirsty than pensive and philosophical Ongs. They form the base of the military class. Oceanids believe men to be bearers of life, and women - vessels of death. Anthropomorphous look of Naiads serves as proof for this statement. They look exactly like people of the upper world - the afterworld, and besides, there are no immortals among them.
Martial arts is not the only thing that Naiads are famous for. Their hypnotic singing, not really appreciated by people of Aelion, drove mad many Ongs. Even young Tol-Monter, the great god of Oceanids himself, fell into an enchanting trap of a subtle Naiad - and made her a queen.