Nereus

In Greek mythology, Nereus (Νηρεύς) was the eldest son of Pontus (the Sea) and Gaia (the Earth), a Titan who with Doris fathered the Nereids, with whom Nereus lived in the Aegean Sea. In the Iliad the Old Man of the Sea is the father of Nereids, though Nereus is not directly named. He was never more manifestly the Old Man of the Sea than when he was described, like Proteus, as a shapeshifter with the power of prophecy, who would aid heroes such as Heracles who managed to catch him even as he changed shapes. Nereus and Proteus (the "first") seem to be two manifestations of the god of the sea who was supplanted by Poseidon when Zeus overthrew Cronus.