To clarify: I was specifically asking for battle tactics, that is, open combat. Certainly, subterfuge and assassinations will have played their part in the insurrection, but it's not hard to conclude how those have looked like. Battles are, however, complex things even without having to counter magic.
OK. Got it.
- Stopping cavalry by simply placing a wall in front of it, shouldn't that work pretty well? Many area-of-effect things, like fireballs or worse, shouldn't they also be quite effective?
Sure, both would be effective, but are fairly limited in use. Meaning: range and area of effect. Current gaming practices aside, battlefields tend to be rather large. Often spanning miles of "front." Sure, the more modern you get the bigger the battlefield (because technology demands it), but I think that magic could also have similar results. Though not quite as much due to the limited nature of magic. (the aforementioned: range and area of effect). I don't know the specifics of what you have going on here (i.e., how many high-level mages, mid-levels, low-levels, etc... or their disposition in the various spell lists), but I am assuming not many. This is for two reasons: 1) it takes a long time to become a mage powerful enough to do such things, and 2) it sounds like the mages in power were jealous of their powers and wouldn't like others getting powerful enough to challenge them. Both of these things would keep their numbers low. So, I don't think they are able to create these walls spanning hundreds or thousands of yards as would be needed to completely stop the charge of a decent sized cavalry unit. (Again, I don't know the numbers you are working with, so I am assuming here.)
- If I, as a sorcerer prince, do know that ambushes are to be expected, wouldn't I employ detection magic? Which would you prefer, if you had a choice?
- Infiltrators, shouldn't they be easily spotted with magical means? And wouldn't magical infiltrators be a big threat to the Steel Rebels? What would be their most likely reaction to magically supported infiltration?[/quote]I'm going to combine the answers of these two as they are similar questions.
Detection magic in RM kind of sucks. I do think it was built that way, so players can still be surprised. Most detection spells cover a massively huge area of 5-feet!!!! Ranges are good, often in the hundreds of feet, but that minuscule area is pathetic. The only one worth a damn - and it is easily able to be handled too - is the Presence spell of a Mentalist. Ten feet per level radius, so a 20th level has a 200-foot range, 50th = 500-feet, etc... As cool as that is, it only detects the presence of sentient creatures.
So, if you are in the middle of their army, they got tons around them, so hiding among them should be easy. To determine that you are not supposed to be there, means focusing on
you. So long as you don't stand out or draw unwanted attention to yourself, there should be no reason for that to happen. Presence is the only spell that mundanes have no ability to counter - its not like they can stop being sentient. (I take that back. They can. It's called dying. Now they are an inanimate object, no longer subject to the spell.) All the others just enhance existing senses. While this will make sneaking by them harder, it does not make it impossible.
As for the mages infiltrating the Steel Rebels: sure, they will be able to do so with shape/appearance altering magics. But, again, only the mentalism spell users can truly emulate an individual well to near perfection, so much so that figuring out that they are not actually that person might be as close to impossible (without magic) as to be impossible. Just watch any Mission Impossible movie or TV episode to see how infiltration can be handled - both well and not-so-much.
On the battle-field adaptability is key. The ability to alter your tactics to fit the new situation on the fly is immensely important and the commander that cannot does not survive long. Stealth/subterfuge/trickery is still important, like making them think you are attacking from one direction when you are actually coming from another (or not at all - you are attacking someplace else completely). So, I think there would be certain "hero-commanders" of the Steel Rebels, ones that showed their ability to adapt and win, even though the odds were long and things seemed unwinnable.
I do think you are going a little too gung-ho on this "must hate everything magic or seemingly magical." (Of course, your game and all that.) But, as a matter of psychology, if they hate everything that seems magical / can affect things magical, they would hate their own, normal weapons too because they can kill magical beings. This is like hating silver because it hurts werewolves or wooden stakes because they kill vampires. So, I would suggest pulling back a little on that, and giving them a material that helps them against magical beings/powers, though, by all means, make it rare. Perhaps the leadership has rings or another talisman they have to wear in order to prove that they are not mages - for it burns the skin of magical beings (mages and others). This means, that if they are in doubt about someone and they have access to this material, they can perform a test. That would help against magical infiltration, but because of the rarity, many infiltrators will go undiscovered.