Virtual Reality and Artificial Intelligence provide suitable techniques to improve computer games quality. While the former offers mechanisms to model environment and characters' physical features, the latter provides models and tools for building characters, namely Synthetic Actors or Believable Agents, which can exhibit intelligent social behaviour and express personality and emotions. The current architecture proposals for Synthetic Actors do not fully meet the requirements for tong-term games development, such as strategy and adventure ones, it is necessary to guarantee both personality stability and reactive emotional responses, which may be contradictory. In this work, we propose a new Synthetic Actor model that tightly connects emotions and social attitudes to personality, providing a tong-term coherent behaviour. This model has been applied to two games presented here as case studies.