game master

A game master is the participant in a role-playing game responsible for describing the fictional world, portraying non-player characters, and adjudicating the outcomes of player actions. The role goes by different names in different systems — dungeon master in Dungeons & Dragons, keeper in Call of Cthulhu, storyteller in the World of Darkness — but the core function is the same: maintaining the shared fiction that the other players act within.

Game mastering involves preparation (designing situations, mapping locations, deciding what non-player characters want) and improvisation (responding to player choices that no preparation anticipated). The balance between these varies by system and by group. Some games assign the game master broad authority over the fictional world; others distribute narrative control more evenly. A few systems, such as Fiasco, eliminate the role entirely.

The game master also mediates social dynamics at the table. Because they control pacing, spotlight distribution, and safety tool enforcement, the role carries responsibility for whether all players have space to participate. Session zero conversations typically establish how a particular group handles this.