The concept of sustainable building design is personified EPIC building. The cartoon character provides a motivational message, energy-saving guide, useful tips, and energy consumption data in an appropriate location. The ultimate goal is to changing building residents’ behavior for energy saving. To do that, the Epic affects their tiny behaviors in everyday life using a cartoon. The Epic shows funny animations with a message when he recognizes a user in a particular location. The animations use several different kinds of a message as a hidden strategy.