Zahhak, the most central demonic creature in Shahnameh, equivalent to Avestic Azdyhak and the three headed dragon of Indo-Iranian origin is one of the most distinct evil creatures in Mazdisna writings. Numerous interpretations of the Zahhak’s myth were made and considering the fact that Zahhak is of the Arab origin in Shahnameh, and assuming that the plain where horsemen fight with spears (Dashte Savarane Nayzehgozar) a place within Iraj’s domain in Shahnameh is one with the Arabic Sahara, certain interpretations regard the Zahhakk’s myth as a legacy of the migrants’ battles with the races of the Sami origin such as Assurians, Sumerians, and Babylonians. While criticizing other interpretations this research shows that Zahhak’s myth could be related to the Underworld Serpent God in the ethnic cultures of Iran’s plateau and its adjacent lands. According to this myth, the best youth were sacrificed for the God of the Underworld and the dragon killing myth is not a relic of a historic battle, but a symbol to end this bloody tradition of the prehistory.