The Game Master, or GM, of a game in the Destroy the Godmodder series is the person in charge of creating and running said game. They are expected to post the thread, explain its rules and provide backstory, and then continually update the game in a turn-based format until the game is finished. Every turn, the GM must take all the actions of the players and respond to them, judging which actions worked and which didn't. Then, they must keep track of the entities summoned by the players and have them attack, and then record changes to entity stats.
The GM should also be able to keep gameplay varied by introducing various plot elements such as bosses and gameplay events, and must also allow for player interaction to influence the game in unseen ways to prevent railroading. At the same time, the GM must also be able to create a plot for the game and develop it occasionally in the form of storyposts.
In-universe, all GMs of canon games gain their power from either the Green Sun or the Red Sun and become First Guardians for the duration of the game. This allows them to access an Update Terminal and directly interfere with the events of their corresponding game by judging the actions the Descendants make in the game's universe. In the case of Green Sun GMs, they are influenced by The Operator.