For me it was “Hollyhock God” from Nobilis.
Why do game designers do this? Does anybody, anywhere, actually use these weird terms while actually playing?
EZD6 GMs are referred to as “Rabble rousers”.
Alien uses Mother
…TSR’s marvel RPG used judge, but i prefer referee from the original D+D little white books…
…invisible sun uses gamemaster but its players are called vislae…
World of Darkness and other Storyteller/Storytelling system games call their GM the Storyteller, which I think is a good title for it.
As for why designers make up their own, the term Game Master is pretty generic, and kinda boring, and they want to create something unique and/or more flavorful to their games. The term “Dungeon Master” is also owned by Hasbro and also only really makes sense in more Tolkien inspired fantasy games where heroes are crawling their way through dungeons.
In John Wick’s Wilderness of Mirrors, the GM is called CONTROL, if I am not misremembering.