The idea that plural demons acted in concert – as a body, or in a body – was widespread in patristic thought, and was figured in a number of ways. One of the most popular and powerful of these was the notion that multiple demons acted like an army of soldiers, co-operating together to tempt and attack their human opponents, often under the direc- tion of their singular commander-in-chief, Satan. Indeed, this overlap between plural creatures and singular action is encapsulated in the Gospel stories of the Gadarene exorcism in which a demon declares himself to be ‘Legion’. This paper will demon- strate the popularity of the metaphor in Latin, Greek and Syriac writers of the second to fourth centuries, working across a range of genres. In particular, it will examine the treatment of the notion of a demonic army in scriptural exegesis (in accounts of the mythic fall of the rebel angels after Satan), and in ascetic treatises (in accounts of the assaults on desert-dwelling solitaries by demonic troops, and even by demons disguised as soldiers). The second part of the article will analyse some particular instances in which the harmony and co-operation between demonic minions and diabolical com- mander was imagined to break down, as, for instance, in their very different reactions to Christ’s descent to hell in Ephrem’s Nisibene Hymns. Overall, this article will explore the tensions within and between accounts of armies of demons, to demonstrate the varied functions and limitations of this military/body metaphor.