Numerous concepts have been created to justify governance. The system of knowledge-power, often produced by religious scholars, has sought to define and establish governance in accordance with historical contexts in relation to the Almighty God. The concept of the shadow of God (Zellul-lah) is one of these concepts that has been defined and used for the rulers in the form of a system of beliefs. This notion is often considered in conjunction with the notions of legitimacy, such as Farreh Izadi, as being a synonym in a sense, while its semantic discrepancies in the historical context has been ignored. Therefore, this study seeks to answer the question of how the philosophy of the notion of  Zellul-lahi in the era of Nader Shah was defined in the system of knowledge-power inter-relationship, and its functionality. Using the theoretical discussions of Foucault's “knowledge-power” method, as well as the "history of concept" approach, this research will explain the theory of Zellul-lahi in the era of Nader Shah and its consequences. The results of this study show that in the Nader shah era, there was a breakup in the “knowledge-power” system. This is true by taking into consideration that official-historians as producers of knowledge tried to define a different position for it due to Nader Shah’s separation from the legitimizing system of the Safavid era. For this reason, the concept of Zullul-lah in this age, as an independent approach, and in direct connection with God in the system of knowledge and power, has been established and exclusively used for Nader. This new system of knowledge-power, which was formed in this era, later led to a great change in the history of Iran, and helped in the evolution of the socio-political order of our country.