While the conceptual models on conflict, security and regionalism have evolved and augmented with time, East African pastoral relations remain subject to simplistic explanatory analyses that view pastoral conflicts as cross-border community conflicts and small arms as part of their cultural heritage. This article strives to find a more nuanced understanding of the relations of pastoralist communities and the role of arms in the perennial cross-border conflict. It uses a regional security complex (RSC) approach, first proposed by Barry Buzan and subsequently moulded in ‘new regionalism’ perspectives, which emphasizes the intricate web of pastoralist relations shaped by their need for security, where their identity and livelihood (cattle) remain at the centre. Taking this further, it develops the concept of a Karamoja security complex (KSC) as an appropriate explanatory framework. Through historical analysis and primary data collected among the Nyàngatom in Ethiopia, the research reveals a regular and complex pattern of conflict moulded primarily by the fundamental need for security.