As a director keen on deviating from the conventional parameters of particular genres, Denis Villeneuve presents an uncanny amalgamation of genre conventions and eclectic thematic perspectives throughout the worlds he creates. In discussing his approach to directing Sicario (2015), Villeneuve stressed his emphasis on avoiding the assumed ‘paths’ of specific genres and the refinement of their conventional processes (Lambie). This appeal to the negation of genre conventions can be observed in both Sicario and Prisoners (2013) as, despite their common recognition under the genres of crime, action or drama, their idiosyncratic nature stems from the inclusion of horror and art-horror genre conventions. In this chapter, I will identify and analyse the role and representation of evil through the films Prisoners and Sicario. In conducting these observations, I argue that it is possible to extract a consistent representation of the central characters of these films through the introduction of the concept of ‘hidden’ monsters. Within this context I establish an action-, affect-, and motivation-based criterion of moral accountability as the foundation of the identification of evil agents within the context of Sicario and Prisoners. Through the development of this criterion, this chapter goes onto to propose an alternate definition of the term ‘monster’ through an analysis of Noel Carroll’s writing on art-horror, mainly addressing the text The Philosophy of Horror, or Paradoxes of the Heart (126). This chapter argues in opposition to the strict ‘entity-based’ nature of Carroll’s art-horror theory by departing from the ‘fantastic biologies’ required from this approach and turning to alternate theories of monsters through the work of Cynthia Freeland and Matt Hills (144). The purpose of this approach is to detail a mode of analysis in which we are able to identify antagonistic characters or entities as ‘monsters’ based upon a moral criterion informed by the behaviours and attitudes of a character or entity as opposed to their biological or physiological representation. As this analysis will demonstrate, these characters exist within Sicario and Prisoners as monsters not in the biological sense Carroll demands, but as ‘realistic’ human monsters who nonetheless align with Carroll’s notion of interstitiality through the corruption of their assumed sociocultural identities.