This article examines how the accelerated development of semi-autonomous or autonomous armed robots may challenge traditional conceptions of military virtue. While early reflections on the ethical implications of military robotics have focused primarily on utilitarian or deontological/rule-based considerations rather than questions of virtue or character, a comprehensive inquiry into the ethical impact of armed military robots must not ignore the role of military virtue in restraining and legitimizing armed conflict. Armed military robots problematize this role in three ways: first, by potentially leveling the distinction between mere military action and virtuous military service; second, by possibly diminishing the scope of the military profession and its cultivation of military virtue; and third, by undercutting the expectation of virtuous motivation in warfare that gives rules of engagement at least some restraining force and helps to distinguish the practice of war from mercenary or criminal violence. I suggest that by initiating or accelerating such shifts in the meaning and practical scope of military virtue, the widespread deployment of armed military robots may have ethically deleterious effects on human soldiers and civilians independently of whether optimistic utilitarian predictions of reduced casualties and collateral damage are realized.