Mist: An Interactive Storytelling System With Variable Character Behavior

Despite advances in game technology, most stories constructed by game designers remain inherently linear in nature, and player actions often have limited impact on the central story. In interactive storytelling approaches, an important challenge is the creation of stable yet dynamic environments to allow the emergence of unscripted stories involving both human-controlled characters and autonomous non-player characters (NPCs). In this paper, we present an architectural design for creating open-ended, interactive storytelling systems in which story structure emerges in real time and in response to player actions, thus providing a greater variety of game experiences than more scripted approaches. We present a partial implementation of the approach in a virtual environment populated by multiple NPCs that exhibit stable but interesting autonomous behavior. Finally, we present experimental results that demonstrate the scalability of the approach and variability of NPC behavior that it produces.