The legitimacy of rule in the Shahnameh is realized by emphasizing the Farr and Farr e Yazidi and Kayani. Despite these, the Shahnameh also emphasizes in some cases that Farr e Yazidi and Farr e Kayani are not always a protective halo of politics and power, but rather a false ladder that leads to autocracy and self-deification. According to Ferdowsi, this is the fate of the Pishdadi king of Jamshid. In the case of Kai Káús, the lack of some moral and social qualifications can also eliminate the halo surrounding the ruler. In these two cases, the political metaphysics of the ruler seems to be inadequate and requires a moral perspective. The representative of this moral perspective is Fereydoun. However, Fereydoun's political metaphysics, along with his moral competence, finally reach their perfection in Kai Káús. Such a development necessitates the creation of a desirable governing institution and structure. But the inevitable logical consequence of such an institution and structure is the absence of the king as the ruling and full-fledged subject of politics. This article, while examining two forms of political legitimacy (metaphysical and moral) in the four mythical and epic kings of the Shahnameh, concludes that Keykhosrow goes beyond the limitations of the first two legitimities and comes to project the institution of governance, an institution that is focused on the efficiency, effectiveness, and general satisfaction of the subjects, rather than the divine grace and moral competence of the king and his personal presence in politics.