This chapter explores key episodes of extreme violence in the context of wars between Greek-speaking groups in the Hellenistic period. Case studies explore the phenomenon of destruction of Hellenistic cities and interrogate whether such destruction in warfare should be counted as genocide. The chapter identifies and compares conditions for extreme violence in the Hellenistic period, which was marked by continual warfare. It argues that competing discourses about justice, together with different emotional regimes related to justice, including anger, pity, and shame, serve both to moderate and intensify violence throughout this period. Where violence is taken to be just, views of justice as legitimate punishment and vengeance can ground acts of extreme violence, while view of justice as reasonable, equitable and gentle may moderate violence but could also be activated to justify extreme violence, if it is taken to be responding to extraordinary provocations or ethical and religious violations. These traditions of justice and emotional norms in the context of warfare in turn sit within a range of other cultural and political commitments which may both moderate and provoke extreme violence, including the development and maintenance of civic identity, legal and religious norms, and considerations of economic and political power.