“Secret societies”, “traditional hunters”, “charms” and “mystical weapons” are recurrent terms when analyzing some of the present armed conflicts in the Sub-Saharan region. However, though spiritual beliefs shape armed groups’ behaviour, and such beliefs are integrated into the modus operandi of some armed groups, the role of these beliefs in warfare is largely overlooked. Far from being something anecdotal or incidental, the invisible world plays a role in shaping armed groups’ behaviour and framing warfare dynamics. Spiritual beliefs might influence the respect afforded to international humanitarian law and international human rights law. Such beliefs may also serve various strategic functions, including for legitimation of the group, mobilization of support, control, cohesion, discipline, motivation and protection. Digging further into the matter and understanding how such beliefs impact the internal dynamics of armed groups and their external relations, including with the State, other armed groups and communities, is an essential part of understanding armed conflicts and their aftermath.