The article describes how certain motives can combine with the exclusion of people from the moral universe, leading to torture, genocide, and mass killing. Personal goal theory is presented as a framework. Personal goals and moral values have ranges of applicability from which certain groups may be excluded. When there is conflict between goals and values, stringent moral values can be replaced by others that allow harm doing—a process termed moral equilibration. The psychological and motivational sources of exclusion include devaluation of groups, just-world thinking, self-distancing by euphemisms or by an objectifying perceptual stance that reduces empathy, and ideologies that identify enemies. Certain cultural characteristics create a predisposition for group violence. Together with intensely difficult life conditions, they give rise to powerful motives and lead to ways of fulfilling them that turn the group against a subgroup of society. As they harm their victims, the perpetrators and the whole society change, progressing along a continuum of destruction that can end in genocide. Bystanders often encourage perpetrators, and they themselves are changed as they passively face the suffering of victims. However, bystanders also have great potential power to inhibit the evolution of increasing destructiveness.