  In this demo paper, we introduce SAPIEN, a platform for high-fidelity virtual
agents driven by large language models that can hold open domain conversations
with users in 13 different languages, and display emotions through facial
expressions and voice. The platform allows users to customize their virtual
agent's personality, background, and conversation premise, thus providing a
rich, immersive interaction experience. Furthermore, after the virtual meeting,
the user can choose to get the conversation analyzed and receive actionable
feedback on their communication skills. This paper illustrates an overview of
the platform and discusses the various application domains of this technology,
ranging from entertainment to mental health, communication training, language
learning, education, healthcare, and beyond. Additionally, we consider the
ethical implications of such realistic virtual agent representations and the
potential challenges in ensuring responsible use.
