Hypothetically, a high-level mage (or someone who stole their stronghold) finds themselves with a stronghold that has been enchanted, such that the structure is itself a magic item.
(One such example, which certainly has nothing with the fact that I’m watching Escaflowne again, would be a flying castle.)
Would the cost of the enchantment count towards stronghold value for the purpose of securing a domain?
(For the curious, enchanting a castle to fly would cost approximately 229,500 gp in gold and the same in special components. I’ve assumed that the ‘make a castle fly’ spell is a 9th level ritual, based on the fact that you can’t actually construct it with the PC spell design implied rules, with ‘fly as magic carpet’ topping it out.)
Even more mundane enchantments might be interesting. There are vague allusions in game of thrones to the shadow creatures Melisandre creates being unable to pass through the outer castle walls.
It's tough to say if it contributes. All the examples of using magic in construction are mostly centered around being able to save money. I feel like in the case of the flying castle, the importance of the fact that it flies isn't that it's got a higher stronghold value, but that you could theoretically change where it was securing.
Ooh, that's a good point - somewhat akin to the mobile air superiority bubble of an aircraft carrier.
Better, even, for things like establishing line of supply for armies, or temporary zones of control through preferred paths, etc.
This is definitely an area of Judge's discretion. For instance, using wall of stone to thicken the curtain walls, that seems like it certainly would increase stronghold value. But using wall of stone to add a veneer of alabaster over the keep wouldn't.
Flying castles probably need their own blog post...