>>5852827If I remember, The Expanse (maybe the novels?) began as a roleplaying game campaign created and played by the authors.
I think Firefly / Serenity (the Joss Whedon one) might also have been based on a Traveller space rpg campaign he played. I believe perhaps some of the Tom Clancy books (maybe the submarine one? I don't know anything about Clancy beyond seeing the logo on Ubisoft Ghost Recon / Rainbow Six games lol) were also based on tabletop or wargaming dice roll combat simulations by Tom Clancy himself.
So I am interested to discover if there are some other popular franchises that originally began as ttrpg campaigns by their authors / creators hehe, but with their roleplaying origins now forgotten.