Endeavoring to distinguish acts of evil from acts of mundane wrongdoing, many philosophers have identified a particular kind or degree of harm as definitive of evil (Card 2002; Russell 2007, 2012, 2014; French 2011; Calder 2003, 2013, 2015). 2 These accounts purport to explain why acts like genocide are evil while acts like theft are simply wrong. My principal aim in this essay is not to critique the details of the arguments found in these theories of evil; in general, I find that each account contains important truths about the nature of evil and the kind or degree of harm that typifies it. Rather, I argue that an analysis and description of evil harm alone does not provide a complete understanding of evil action. While definitions of evil as harm focus mainly on synchronic, or current time-slice, features of evil action, I argue that evil action is a phenomenon whose history is often significant to understanding it as evil. Correspondingly, a diachronic approach reveals two critical attributes of evil. First, we discern conditions that facilitate evil’s distinctive harm. Evil action develops out of a normative relation that obtains between the victims and perpetrators of evil; it is an asymmetrical relation of power based on fundamental vulnerabilities and their exploitation. 3 This relation is frequently enduring over time. When it is, and the exploitation of fundamental vulnerabilities occurs, then evil obtains. Second, the moral history of the victim of a putative evil act is often relevant to whether the act is in fact evil. To support this latter claim, I examine three different approaches for assessing the relevance of the past evildoing of a former perpetrator-turned-victim. Again, my aim is not to supplant, but rather to complement, many current harm-based accounts of evil action by drawing our attention to the diachronic features of evil action that are significant to our understanding the nature of evil.