In the years between 1880 and 1914, an increasing number of Western states became involved in colonial expansion, and this age witnessed countless colonial wars – wars generally characterised by extreme violence. While similarities (and differences) have regularly been noted in the violence employed by the different colonial powers of this time period, no concerted attempt has as yet been made to capture this extreme violence as a transimperial phenomenon. This my paper attempts to do, drawing on a number of case studies as well as contemporary literature from the British, German, and Dutch Empire. I argue that a tendency to focus on certain national military doctrines or military cultures has often obfuscated the underlying unity in the employment of extreme violence throughout the imperial sphere, a unity that instead can be found on the level of a number of specifically colonial notions that both generated and legitimised transgressive violence. Secondly, this paper establishes the different sorts of transimperial connections that made transfer of knowledge across imperial borders possible. While these connections were differently configured than the transimperial links that have been uncovered in other fields, they were nevertheless significant in transferring knowledge between different actors and sites of colonial war.