This thesis is a comparative, empirically driven, small-n, comparative study that attempts to answer the question: Does morally motivated violence increase the level of conflict brutality? The study argues that higher levels of moral violence will lead to an increase in conflict brutality due to psychological processes that limit restraint. Two rebel groups are studied, the Islamic State and Jabhat al-Nusra li al-Sham in the context of the intrastate conflict in the Syrian Arab Republic. Motivations of violence are measured through an idea analysis and are operationalized in both instrumental and moral motivations. The Islamic State shows higher rates of conflict brutality and are more morally motivated in their acts of violence than Jabhat al-Nusra, who show more instrumental objectives and are not as brutal. The study concludes that there is a relation between morally motivated violence and conflict brutality and urges future research to further establish this relation.