The five Arthurian romances of Chrétien de Troyes were hugely influential in establishing King Arthur’s world as one that could easily expand to include the adventures of a seemingly endless group of chivalric heroes. Chrétien’s use of character details to connect his romances and suggest a shared fictional world inspired other romance writers as well as medieval translators, illustrators, and manuscript copyists and compilers. The result was a multimedia Arthurian universe akin to the modern narratological concept of the transmedial storyworld. This storyworld relied on the recognisability of the Arthurian knights as characters and existed in many different forms across written and visual media, including the unique combinations of text and image that appear in different manuscript witnesses of Chrétien’s romances. Emphasising the utility of both individual manuscripts and modern narratology, this article investigates three manuscripts that contain romances by Chrétien: Paris, BNF fr. 1450, Paris, BNF fr. 1433, and Montpellier, Bibliothèque interuniversitaire, H 249. Through examining the distinct arrangement, editing, and decorative choices in these manuscripts, I argue that they illustrate the potential of character as a means of worldbuilding, not only for medieval authors but also for other creators and audiences.