The War in Donbas was in its early phases largely fought between non-state volunteer battalions and separatist forces. Yet unlike the expected theories of non-state actors, the war witnessed limited and symmetrical acts of escalation and rather conventional warfare. Building on primary Ukrainian sources, I argue that this limited escalation stems in part from shared cultural and military norms — a common normative framework — possessed by the belligerents. The contribution of this article is an empirical chronology of the War in Donbas, as well as a discussion of the influence of culture and norms in escalatory dynamics and use of force.