It has become something of a cliché to introduce theoretical explorations of characters in contemporary culture by noting their ubiquity. Yet, it remains true that characters are represented in a broad range of media forms that includes literary texts, plays, comics, films, television series, and videogames. No less importantly, characters are often also considered as entities that move across media forms in various ways, leading to a complex set of theoretical problems at the intersection of medium-specificity and transmediality. While this is not a new observation, the increasing sophistication and popularization of generative AI platforms has provided yet another potentially productive challenge to the field of character studies. This includes questions such as how AI chatbots can be used to generate representations of a broad range of different characters and how generative AI can be integrated into videogames to create what could be described as AI NPCs. In light of these more recent developments, the chapters collected in this volume explore the diverse forms and functions of AI characters from different theoretical perspectives, and using a range of different case studies.