Wars and genocides only bring desolation. Of course, we first think about the dramatic psychological consequences of those who survived extermination or those who have witnessed their families and friends being killed or mutilated. Psychological and neuroscience research have shown that surviving a psychological trauma leaves long-lasting imprints on individuals with notable life-long post-traumatic stress disorder (PTSD) symptoms, which can also extend to the following generations. Importantly, the psychological disaster observed in the aftermath of a war or a genocide not only touches the victims, their relatives, or their descendants. It also has disastrous consequences on the mental health of the assailants. The chapter argues that in order to stop the cycle of conflicts, we must also understand how both victims and assailants are impacted at the psychological level by their respective experience, and how to help them overcome their demons and potential feelings of revenge. Taking care of their mental health is a step towards stopping cycles of conflict.