How much text about the game world do you have? Does this amount compare favorably to the volume of text required to train an LLM?
Answer those two questions and you will realize why your idea doesn’t work.
Answer those two questions and you will realize why your idea doesn’t work.
So I don't think the necessary amount of text that you need to train the AI on is as insanely large as you imagine (but of course nevertheless a lot of texts have to be written - this is the price of having "much more dynamic" AI characters in the game).