This dissertation is a study of the dynamics of armed mobilization and participation in non-state armed organizations in the province of South Kivu, eastern Democratic Republic of the Congo. It asks one of the fundamental questions of the study of violent conflict: Why do people participate in armed groups? In addressing this central question, it also addresses the inter-related questions of how do people come to participate in armed groups and who participates in these groups. I make three main arguments. First, contemporary armed mobilization is driven by two ‘macro’ factors in rural eastern DRC, the necessity to organize and provide protection to the sociopolities that constitute rural eastern Congo on one side, and the more accumulative dynamics of labour mobilization and control that have long characterized the region and have taken novel forms with the development of an economy of predation. The protective dimension in particular has often been left out in recent accounts that have focused or economic agendas of armed groups. Second, the ‘social architecture’ of armed mobilization in the region has changed to reflect the social implantation of armed organizations in rural eastern Congo, resulting from the novel roles they play in these societies and the adaptation of these societies to their presence. As a result, modes of recruitment and control reflect the multi-faceted influence that these organizations have over rural societies. Third, I argue and show that individual determinants of participation are not time invariant, they evolve over time and reflect the changes in outlook and motivations of participants that results from the social implantation of armed organizations, but also as a result of the process of participation. In order to make these arguments, I use a mixed methods approach that combines a qualitative analysis based on interviews carried out during 9 months of fieldwork in the province of South Kivu, and a quantitative analysis based on original panel data collected through a survey of 1072 individuals and 134 villages of South Kivu.