Greek sea gods conform to a single type: that of Homer's "halios geron" or Old Man of the Sea: Nereus, Proteus, Glaucus and Phorkys. These sea gods are not as powerful as Poseidon, the main god of the oceans and seas. Each one is a shape-shifter, a prophet, and the father of either radiantly beautiful nymphs or hideous monsters (or both, in the case of Phorkys). Nymphs and monsters blur, for Hesiod relates that Phorcys was wed to the "beautiful-cheeked" Ceto, whose name is merely the feminine of the monstrous Cetus, to whom Andromeda was due to be sacrificed. Each appearance in myth
The God Beneath the Sea Eurynome and the two goddesses tell him various Greek creation myths. The novel continues with myths of the Olympians and the age of gods and mortals, and concludes with Hephaestus returning to Olympus, having been cast down for a second time after reproaching Zeus. Garfield, Blishen, Keeping, and Longman collaborated on a sequel entitled "The Golden Shadow" (1973, ). It is based on myths of the later heroic age, when divine activity was limited. "The God Beneath the Sea" is divided into three parts. Part one begins with the image of the infant Hephaestus plummeting from Olympus to the ocean.