A sea god, otherwise known as the Old Man of the Sea (Halios Geron), father of the Nereids. At first shown with a fishy body, then wholly human. He attends many marine occasions, and the wedding of Peleus and Thetis (his daughter). Like other marine deities he is able to mutate into other shapes or fire. Herakles wrestles with him, and is sometimes shown destroying his house.
Above: Herakles and Nereus. Detail from Athenian red-figure clay vase about 525-475 BC. London, British Museum E162. Photo. Mus. XCIX-C2 © British Museum