Nereus knew all the secrets and routes of the ocean, dominated the marine element and transformed himself into any animal, object, or plant in his kingdom. Along with his fifty daughters, the Nereids, they guided the sailors and helped the fishermen.Nereus knew all the secrets and routes of the ocean, dominated the marine element and transformed himself into any animal, object, or plant in his kingdom. Along with his fifty daughters, the Nereids, they guided the sailors and helped the fishermen.