Thank you for your feedback. As far as I remember, the Orcs in the Hero and Veteran difficulties are free and unconstrained (definitely in Hero difficulty), and they don't have any scripts for staying put; it's just the AI's stupidity. In the final map, everything is scaled up precisely because it's the final map; with proper development, even I, a rather mediocre player, managed to complete it more or less successfully. And the lore explains it quite simply (although, perhaps it should have been included somewhere, but I considered it unnecessary): this is the Castle of the Order of the Dragon, and all races were members except for Orcs and Demons, as far as I remember, so anyone could be tasked with guarding the castle. I hope I was able to clarify these points.
Ah, if it's the Castle of the Order, then it makes sense. Thank you for the explanation.