When game worlds were simply linear presentations of rooms and corridors, it was acceptable to create AI that existed solely in those confined spaces, with controlled gameplay and defined player experiences. As the industry moved to more open world games, static set-piece characters quickly broke the intended immersion of a "living, breathing world." Developers wanted to give the impression that the AI was living in the huge, dynamic world that they inhabited, as well as to allow for non-linear play choices and emergent end-user experiences. The quandary was developing a system that allowed ambient AI and undirected systemic gameplay, but still supporting structured narrative. This two-part session features developers who have worked on games such as Far Cry 3, Saints Row 4, and upcoming titles from Avalanche Studios, and will show concrete examples of how notable open world games provided characters that offered dynamic gameplay opportunities while still preserving scalability of design and fidelity.