Worldbuilding: No Explosives Greater Than Black Powder

[Zaune]

Demolishing large building such as skyscrapers would be very hard to demolish - essentially they would have to be dismantled, unless you can live with the results of them falling down uncontrolled.

Not as much as you'd think. Ever heard of a man by the name of Fred Dibnah? He got to be a minor celebrity in this country after appearing on a BBC documentary and demolishing a disused factory chimney without using any explosives at all; he'd knock a load-bearing section of the base out with a jackhammer, prop it with lumber and pile kindling around it, then put a match to it and stand back to watch the show. I don't think he ever attempted to make a building fall within its own footprint, especially not a skyscraper, but it wouldn't be hard to apply the same principle.

[Darmalus]

To tiptoe around the topic of whether or not and how internal combustion works - what are mages capable of (and not) in the setting? You mentioned it takes a lot of effort to train one to battle-readiness, but could a mage levitate a tank if the combustion engine doesn't work, or create huge blasts of energy to shame blackpowder arms, or increase the efficiency of a steam engine to make steam tanks viably powerful?

My immediate thought when given a setting where all new technological advances in explosives are rendered meaningless by fiat, but they already have magic, was that they'd just start a magical arms race instead.

Wizards are capable of a tremendous number of things at potentially staggering levels of power. A specialist could probably levitate that tank then hurl it like a catapult stone, but he probably wouldn't be able to do much else any better than a inexperienced student. Think of magic spells as muscles, extreme levels of performance require extreme amounts of time, effort and money to both reach and maintain. As a result specialists tend to be rather vulnerable to battle mages who have broad and reasonably deep abilities in both attack and defense, or even just focused mundane attacks. A bullet in the brain pan kills you quick, wizard or not.

So the theoretical utility of a wizard is counterbalanced by both expense (hazard pay since they will be a sniper and artillery magnet) and getting them in the first place. Short of divine intervention it takes months to travel from one crystal sphere to another. So if no one local is able or willing (or can't be forced) you may be forced to undermine the castle wall the old fashioned way instead of having an earth specialist do it in half an hour. FSM help you if the earth wizard is on the defenders side.

Enchanting is the best bet for enhancing your military, since you can hand off enchanted items to almost anyone or stockpile it for later, but it suffers from some drawbacks. No one has invented a "measuring stick for magic" so enchantments are like handcrafting without measuring tools. Experience let's an artisan create more consistent work, but the nature of enchantment means you can't compare products until they are complete nor rework a flawed enchantment, it's an all-or-nothing business. Still, simple things like sharper swords or tougher materials are reasonably "easy" as far as enchantments go, building a golem is a bit like hand crafting a car by comparison.

Thanks for the inspiration, if anyone would think to use enchanted sub components (stronger fasteners, more insulating pipes, etc.) to approximate interchangeable parts for magic, it would probably be Queen Lilly.