In the later European middle ages, demons were a constant and pervasive presence. They appear in illuminations, paintings, prints, sculpture, songs, literature, and liturgy. Demons are represented as irreverent, beastly, murderous, sexually aggressive, miserable, or gleeful diabolical figures that evoke fear, revulsion, laughter, meditation, atonement, or pity. Their only constant is their mutability. I argue the visual complexity of these representations evoke multivalent interpretations and thus demands closer examinations. The unique forms and inventive iconographic contexts for demon imagery in late medieval and early modern art reveal alternative modes of viewing the infernal non-human. My dissertation is the first art historical study exploring demons–beings at the core of Christianity–as a type of species with complex bodies, behaviors, and sexualities. In particular, I examine miniatures in richly illuminated manuscripts–hand-held texts that invited close looking and intense contemplation for the late medieval devotee. I focus on devils that appear in luxury objects designed for noble or wealthy patrons in order to analyze how these liminal beings embody the concerns of elite institutions and viewers. Specifically, those produced within the shifting milieus of fifteenth-century France, Burgundy, and the Netherlands reflect distinct socio-political fears. Demons indicate not only how dominant cultures define and visualize evil, but also whom they decide to literally and figuratively demonize. Overall, this project fuses and expands medieval and early modern disciplinary and theoretical boundaries. My arguments synthesize visual analysis and historical context with literature, monster theory, animal studies, critical race theory, posthumanism, Marxism, and feminism. I examine images of demons as intricate portrayals of a distinct category of beings – a cultural species– with jobs, genders, emotions, and procreative abilities that reveal structural anxieties regarding race, labor, gender, and sexual violence.