Neris — Piers Anthony

Doris hears a compelling song, the reverse of a siren song because it summons women. Nereus, god of the sea, desires her so he can sire a son after having 50 daughters, and she must go to him; her groin is burning. The result is Neris (siren spelled backward), her half human, half god son, with magical powers. He grows up guided by his shapely half sister Nerine, who is a neried, a minor goddess, nude but invisible to others unless she chooses to be seen. Neris will grow up to fight the pollution of the sea that is poisoning the sea gods, in part by using his attraction for women to defeat a deadly real siren whose help he needs. He encounters things like Ouroborus, the serpent that circles the world, biting its own tail, holding the globe together, and who likes to watch movies featuring serpents. This is wild, sexy fantasy with an environmental theme.