Both rhetoric and composition and transmedia studies contain ongoing examinations of the complexity of author-audience relationships. This thesis utilizes the transmedial concept of ontological security in post-object fandom to examine the various ways "authors" of popular storyworlds and franchises affect narrative stability, and by extension fan and fandom stability, in an increasingly circulated and commercially-driven media landscape. To better understand disruptions in viewers' ontological security, I use HBO's Game of Thrones as a case study, examining the varied ways in which audiences respond to transmediated science fiction and fantasy storyworlds, and the ways in which authors attempt to anticipate or mitigate audience response. In utilizing this televisual storyworld, this study examines various cross-sections between author and audience, transmedia, and television studies through a science-fiction/fantasy (or "fantastic") lens. This thesis posits that the inherent authority ascribed to a text's author(s) and the various ways those authors exert authorial control affects the audience's sense of stability and normalcy, particularly within the context of fantastic storyworlds.