This book examines the emergence, activities and legacies of pro-state paramilitarism in the late and post-Ottoman borderlands during the era of the European civil war (1905-1949). This period was marked by profound violence and acute ethno-political transformation spurred on by the decline and eventual fall of the Ottoman empire and the emergence of a wide array of national and transnational political projects variably shaped by ethnic nationalism, fascism, and socialism. The chapters in this book examine the backstories, trajectories and activities of those who fought in the name of the various ethno-statal agendas, paramilitaries, gang leaders, bandits, and other pro-state actors, across the periphery of the empire and including understudied areas such as Kosovo, Montenegro, North-Western Greece. The book reveals the organization, patterns and logic of ethnic victimization, and the impact of ethnic and paramilitary mobilization in the governance structures and political institutions on the societies at the receiving end of violence. This approach offers new insights into the motivations of pro-state armed actors and challenges state-centric narratives on the history and legacy of nation-building, violence and paramilitary mobilization in the embattled borderlands of the Balkans, the Caucasus and Anatolia.