A role-playing game is a game in which players assume the roles of characters in a fictional setting. Players take responsibility for acting out these roles within a narrative, either through literal acting, or through a process of structured decision-making regarding character development. Actions taken within many games succeed or fail according to a formal system of rules and guidelines.
There are several forms of role-playing games. The original form, sometimes called the tabletop role-playing game, is conducted through discussion, whereas in live action role-playing, players physically perform their characters' actions. In both of these forms, an arranger called a game master usually decides on the rules and setting to be used, while acting as the referee; each of the other players takes on the role of a single character.
Several varieties of RPG also exist in electronic media, such as multiplayer text-based Multi-User Dungeons and their graphics-based successors, massively multiplayer online role-playing games.