This dissertation is the first focused study of images of demons and how they were created and received at the turn of the Southern Song and Yuan periods of China. During these periods, China was in a state of dynastic crisis and transition, and the presence of foreign invaders, the rise of popular culture, the development of popular religion, as well as the advancement of commerce and transportation provided new materials and incentives for painting the supernatural grotesque. Given how widely represented they are in a variety of domains that include politics, literature, theater, and ritual, the Demon Queller Zhong Kui and his demons are good case studies for the effects of new social developments on representations of the supernatural grotesque. Through a careful iconological analysis of three of the earliest extant handscroll paintings that depict the mythical exorcist Zhong Kui travelling with his demonic entourage, this dissertation traces the iconographic sources and uncovers the multivalent cultural significances behind the way grotesque supernatural beings were imagined. Most studies of paintings depicting Zhong Kui focus narrowly on issues of connoisseurship, concentrate on the painter's intent, and prioritize political metaphors in the paintings. This study expands understanding of these images by contextualizing them within contemporary beliefs in the supernatural world, which are reconstructed through a heterodox array of thirteenth-century sources encompassing nuo exorcist rituals, physiognomy manuals, joke books, codes of law, and writings on weddings. This study also examines the psychological impact images of grotesque supernatural beings had on their pre-modern viewers by analyzing original translations of inscriptions written in response to these paintings. This study reveals that paintings depicting Zhong Kui are heavily influenced by religious, social, and cultural currents at the time, despite their better-known political readings; that images of demons share interesting iconographic traits with portrayals of humans of foreign origins and in abject conditions; that and that aside from provoking feelings of disgust and fear, demons served as comic relief and spectacles in paintings which had been largely interpreted as moralistic. This study fills a gap in Chinese demonology—which had focused largely on visual and textual sources before the Six Dynasties and after the Ming dynasty—by examining images of demonic creatures from the Song and Yuan periods. It enriches cross-cultural studies of monsters and the monstrous by offering an analysis of comparable Chinese examples. It contributes to studies of Song-Yuan painting by focusing on a category of images that have been understudied because they were at odds with literati taste. Finally, it adds to scholarship on Zhong Kui by offering new readings on three well-known paintings of the Demon Queller and synthesizing studies on him in literature, religion, and folklore.