GameMaster, short for The GameMaster Puppeteer, is a 50-foot-tall entity that enshrouds itself in darkness. It does not have a physical body, but is capable of telekinetically manipulating his strings. GameMaster has one goal and one goal alone: Total Control. It has the ability to wrap it's strings around any entity weaker than it, with a maximum of 15% of his own power as a limit. Known rescued victims of GameMaster are Toonshow, Venus, Entity 404, Lord X, Pitch, and numerous Sans AUs. As for the people who exceed his power limitations, although he could take control of them, he decides not to because he knows the energy needed would make him vulnerable. Instead, he plays sickening games with them, with the price for losing being their lives. These games include Hide and Seek, Deathruns, Mazes filled with traps, and numerous unique ones created by GameMaster himself. However, those who are skilled and lucky enough to beat one of his games are given the opportunity to have one wish granted, with some rules that are as follows:

1. No wishes involving GameMaster's disappearance.

2. No wishing for more wishes (obviously).

3. No wishing to become unkillable.

4. No more than one desire per wish.

5. No wishing for infinite power.

6. Keep your desire simple and straightforward.

GameMaster is truly a force not to be messed with and a threat you should avoid at all costs, unless you want to become his plaything.