For the past decade, the nexus between ethnic militias and critical resource infrastructure has emerged as a central driver of violent conflict, humanitarian catastrophe, and state fragility across Africa’s most resource‑rich peripheries. This paper presents a comparative case study analysis of three regions, the Niger Delta (Nigeria), Cabo Delgado (Mozambique), and Eastern Democratic Republic of Congo (DRC) over the period 2015–2025. Drawing on primary and secondary data from government reports, United Nations documents, academic literature, and media investigations, the study examines nine thematic dimensions: human fatalities, economic losses, environmental disasters, community grievances, criminal enterprises, internal/external collusion, quasi‑sovereign authority, parallel illicit economies, and the crisis of state legitimacy. The findings reveal a consistent pattern: armed groups weaponise resource extraction infrastructure to finance operations, entrench territorial control, and exploit state weakness. However, significant variation exists in the role of external actors (Rwanda in DRC, France/TotalEnergies in Mozambique), conflict duration (decades in DRC vs. post‑2017 in Cabo Delgado), and environmental degradation (highest in the Niger Delta). The paper concludes that without restructuring resource governance to prioritise local benefit‑sharing, demilitarising infrastructure protection, and addressing historical grievances, these conflicts will intensify as global demand for strategic minerals increases. Keywords: Ethnic militias; resource conflict; critical infrastructure; Niger Delta; Cabo Delgado; Eastern DRC; illicit economies; state legitimacy; quasi‑sovereign authority