NPC

The term "NPC" stands for "non-player character" and comes from the most ancient days of Dungeons & Dragons. Anyone in the game world who is not a player character is an NPC. In traditional role-playing games, the individual who ran the game world for the players (an individual variously known as the Judge, Dungeon Master, Game Master, or many gimmicky titles in later games) would portray all the NPCs that the player characters interacted with. In a roguelike game, the behavior of the NPCs follows their programming (what is, technically incorrectly, called artificial intelligence).