Iasus is a name attributed to several characters in Greek mythology. One of them was the son of Zeus and Electra, also called Iasion, who founded the mystical rites on the island of Samothrace. He was killed out of jealousy by his father, when he realised that Iasus had slept with the goddess Demeter.
Another Iasus was the king of Argos, but it is confusing who his parents were; various sources give a large variety of names as his parents. A different Iasus was the father of the female heroine Atalanta, whom he had with Clymene. He was the brother of Ancaeus, Epochus and Amphidamas. Finally, Iasus was also the name of the father of Phaedimus, who participated in the battle of the Seven Against Thebes and died by the hand of Amyntas.