Nowadays, many games can play on various devices. Multi-platform development in game can help us waste of resources and increase number of market share. That is reason of multi-platform game development if it is interesting. Action RPG is classic game genre, that still popular through years. It is so interesting to use Action RPG for multi-platform game case study. Monster In Thailand has story about invaded monster who make an disorder in tourist attractions. The stages are referred by famous tourist attractions in Thailand. Characters has mixed Thai style with SD scale. Players have to role as hero to get rid of monster in tourist attractions. Players also can improve their character by battle with monster. In the future, if we got fund or any support. We will develop more features in this game such as real-time PVP and in-app purchase.