It is estimated that the self-proclaimed Kurdish autonomy in Northeastern Syria accounts for one-third of the country’s territory, and, despite its unrecognized status, it appears to be one of the key players in the Syrian peace settlement and, at the same time, a political hostage to the situation that has developed in Syria as a result of the Civil War. The present article explores the formation of the self-proclaimed autonomy in Northeastern Syria (Rojava, Syrian Kurdistan, the Federation of North-Eastern Syria, the Autonomous Administration of North and East Syria [AANES]) and puts forward the thesis of Rojava’s emergence as an insurgent state. The first part of the study analyses its political system through the concept of proto-state actors for the Kurdish Self-Defence Forces (YPG) and the Democratic Union Party (PYD). Due to the inclusiveness of the Kurdish Self-Defence Forces, Kurdish non-state actors (PYD-YPG) have acquired the features of a proto-state, going beyond the definition of the “Syrian wing” of the Kurdistan Workers’ Party (PKK). The article focuses on the complex and diversified ethnic composition of the local population within the boundaries of the de facto autonomy. This is manifested in the presence of various political actors and movements, including those based on ethnic particularism. It is concluded that such a political structure is fragile due to the interethnic contradictions between the Kurds and the Arabs in the region.