Non-state war actors have trajectories. While recent research contributions stress the role of material interest as the driving force for the formation of non-state war actors, this article attempts to sketch an alternative explanation for their formation. Based on a data-set of 80 cases and comparative case discussion it focuses on the relationships that leaders and staff members of armed groups entertain before the actual formation of such groups. Three mechanisms of formation are consecutively distinguished, depending on the degree and kind of social relationships that precede their formation. The article discusses the causal settings of each mechanism and reveals in how far state policies in medium term and long run horizons produce what they want to curb: the formation of violent challenges.