What do you mean by system? LLMs are Large Language Models. They are by definition work with text. And they are not designed to work normally with what they are not trained for. But, LLMs are only 1 family of the whole range of AI models. For controlling NPC actions, decisions and other stuff you can use small AI models to make their actions more dynamic. For example, a model that has like 10 input parameters, 3-4 hidden layers and the output layer with a few results. And this thing will actually work for many things, not only for controlling npcs. Even on a microcontroller this thing can be used for operating with fuzzy values. These features for creating AI models you can find in game engines like Libgdx or as a separate framework like Neuroph(for Java).
What do you mean by system? LLMs are Large Language Models. They are by definition work with text. And they are not designed to work normally with what they are not trained for. But, LLMs are only 1 family of the whole range of AI models. For controlling NPC actions, decisions and other stuff you can use small AI models to make their actions more dynamic. For example, a model that has like 10 input parameters, 3-4 hidden layers and the output layer with a few results. And this thing will actually work for many things, not only for controlling npcs. Even on a microcontroller this thing can be used for operating with fuzzy values. These features for creating AI models you can find in game engines like Libgdx or as a separate framework like Neuroph(for Java).