This article advances the Cultural Nexus Mediation Theory (CNMT) as a postcolonial framework for analysing culturally embedded mediation and the authority of traditional rulers in West Africa. The study combines fourteen months of fieldwork in Nigeria with supplementary qualitative and archival material from Ghana, Liberia, and Sierra Leone. The core Nigerian dataset comprises 48 semi-structured interviews, 12 non-participant observations, and a structured survey of 612 respondents across four conflict ecologies. The quantitative analysis is explicitly limited to the Nigerian survey. It shows that respondents reported higher trust in traditional than state mediation and higher reported compliance intention with traditional than state mediation, while individual-level trust was not positively associated with compliance intention. The qualitative evidence instead points to public witnessing, relational accountability, cultural obligation, and the institutional setting as mechanisms through which authority acquires practical force. The article therefore refines CNMT by distinguishing perceived legitimacy, reported compliance, and socially constrained compliance, while treating Ghana, Liberia, and Sierra Leone as comparative qualitative cases rather than additional quantitative samples. Keywords: Cultural Nexus Mediation Theory (CNMT); traditional rulers; postcolonial mediation; insider-partial mediators; West Africa; legitimacy