The purpose of this study is to show typology of Non Player Character(NPCs) and to look out what narrative functions of NPCs are served in Massively Multi-player Online Role-Playing Game(MMORPG). As the relationship with player characters and the propensity of actions, NPCs are classified 4types; passive helper, active helper, passive antagonist, active antagonist. Each type performs different functions of game narrative. Especially passive helper functions as a essential glue of movement in game world and makes the chain of quest narratives. Active antagonist functions as the cause of space perspective and creates dramatic effect of game narrative. Those functions make spacial, dimensional and extensible game narrative.