The Weaponization of artificial intelligence (AI) is upending traditional warfare as the development of autonomous weapons systems (AWS) increases in pace and sophistication. As a result, the concept of the weaponized AI, where a weapon system that, once activated, can select and engage targets without human intervention, creates serious complications and challenges for international humanitarian law (IHL) enforcement. It also raises fundamental ethical questions as to whether people can delegate life-and-death decisions and accountability to artificial agents. Many authors have voiced concerns on this subject, but thus far a comprehensive presentation of the deeper ethical considerations related to AWS is lacking. This article uses a systematic literature review to provide an overview of the most common arguments for and against using AWS. The results from the review indicate that compliance or non-compliance with the core principles of IHL are the most prevalent concerns in the discourse. The lack of accountability also makes for a strong deontological reason against using AWS, although normative ethics represents only half of the theoretical argumentation.