Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. A non-player character, often shortened to NPC, is a character that is controlled by the gamemaster in role-playing games. When this definition extends to video games, an NPC in a video game is usually part of the program, and not controlled by a human. In a traditional role-playing game such as Dungeons & Dragons, an NPC is controlled by the gamemaster. Non-player characters populate the fictional world of the game, and can fill any role not occupied by a player character (PC). Non-player characters might be allies, bystanders or competitors to the PCs. NPCs vary greatly in importance, from the NPC innkeeper seen once by the player characters, to the NPC arch-nemesis who comes back time-after-time again for an entire campaign. While every inhabitant of the game''s world except the PC''s are NPC''s, very few are given any detail by the gamemaster (GM). In fact, most of the minor ones are invented on the spot as needed doing this well is in fact one of the hallmarks of a good GM.