Phorcys is recognized in ancient Greek mythology as the primordial sea god embodying the hidden dangers of the deep ocean. He is notably depicted as the father of Medusa, whom he favors above his other offspring.

Ceto, often referred to as Keto, is the goddess associated with the perils of the sea, including monstrous creatures like sea monsters, whales, and large sharks. In mythology, she mated with her brother Phorcys, resulting in a terrifying lineage of monsters. Their children include Echidna, a fearsome she-dragon; Scylla, a creature that devours sailors; Ladon, the hundred-headed serpent; the Graeae, known for their single eye shared among them; and the Gorgons, infamous for their ability to petrify anyone who gazes upon them. In Simanity, Ceto is also recognized as Medusa's mother.