[Persian] The Iranian primeval king who rules a realm where justice, order and abundance prevail. His name means “twin” and his wife and twin sister is Yimak. As king Yam he fulfils three social functions: he is pious as a priest, strong as a warrior, and rich as a large landowner. He was the favorite of the gods, but he fell from grace when he became disdain and mendacious, and he lost his immortality.
The image is called The destruction of Leviathan by God, thought by some scholars to parallel the defeat of Yam or Lotan by Baal.
Source: Encyclopedia Mythica