Castles are worthless against armies with mages?

[Morrus]

1. Mages do not have Ride as a class skill. You will have to send warrior-mages up in the air who can cast invisibility and have the ability to stay in the saddle. However, this brings us to
2. See Invisibility allows you to see invisible things in your sight range... but neither fighters nor wizards have Spot as a class skill. A Ranger/Wizard would have a few ranks in spot, but the distance penalties mean that the 3 levels of Wizard it took to get See Invisibility reduce the chances of making the spot check for a very distant target.
Of course, it could be argued (and I would probably support it) that you don't need to make a spot check to see something very obviously there, like a person flying in the air*, so maybe this isn't that big of an issue.

*Which, incidentally, now raises the question of camouflage...

You're making things too difficult. If you're doing siege warfare which features stuff D&D wasn't designed for, you need new items and rules. Otherwise the whole thing just isn't gonna play well anyway.

So you have your griffin rider prestige class which is designed to locate and engage flying enemies. Or you have your goggles of flying invisible spotting. Or what have you.

There's an answer to every objection, and it lies in the area of "the game would need a sourcebook covering such engagements". Absenting that, shoehorning D&D combat rules into a mass engagement structure is gonna require some work.

For me, it means let your imagination run wild then work out how to do it. Magic items, artefacts, new spells and classes - all this would be needed to run a satisfying battle if that nature.

 

[Dandu]

Don't they address some of these issues in Heroes of Battle and the Stonghold Builder's Guide?

 

[Morrus]

Don't they address some of these issues in Heroes of Battle and the Stonghold Builder's Guide?

To an extent. Not to the extent you'd need, I don't think. But those books would certainly be a good start. It's a long time since I looked at either!

 

[Jack Simth]

Are mundane fortifications completely useless?
No. They let you do some tricks with line-of-effect that let your soldiers shoot arrows or whatever at the oncoming army while denying your opponents access to most direct magical attacks against your soldiers (arrow slits; if that four-foot tall arrow slit is less than three inches wide, it does not pass line of effect). And if a few of your soldiers are Arcane Archer-2's with some actual casting, this lets you do quite a few nifty things. And it'll also slow down the mundane portion of an occupying force.

Can mundane fortifications be destroyed, bypassed, or otherwise neutralized with good magical tactics?
Yes, absolutely. Castles do not make a perfect defense, not by a long shot. Of course, anything specifically done to neutralize the castle costs some amount of resources. As offense is cheaper than defense, the defender will probably lose in an equal-resource game if the defender depends on the fortifications (especially if you use DMG pricing on the castle...). But they can serve a purpose.

Are Magical Fortifications completely useless?
No, they can cause the attacker to must have certain classifications of resources available - if the entire exterior is built out of Walls of Force (including the gate) per Stronghold Builder's Guide (3.0, granted, but the only source of it's type that I'm aware of), then your opponent must have either teleportation magic, Disjunction, or Disintegrate available. If you add a Forbiddance inside, then teleportation magic is out. If you use some wonderous architecture to put permanent Antimagic Fields just outside your walls of force (again, Stronghold Builder's Guide), then Disjunction is iffy, Disintegrate doesn't work without cheddar, and while you can have a trapfinding rogue remove it, well, that's what guards are for ... and they can use the aforementioned trick that was noted for attacking the castle, that of making use of Shrink Item on heavy objects.

Can magical fortifications be destroyed, bypassed, or otherwise neutralized with good magical tactics?
Yes, absolutely, they just require the attacker have certain things at his disposal to get past them. They're just expensive and tricky to bypass, and leave you playing an expensive game of chess with the defender - although as the attacker, you probably have some advantages.

Does this mostly cover it?

 

[frankthedm]

D&D rules aren't designed to cover this situation. You have to do a lot of the work yourself.

And there's the crux of the issue, the battle is underway and if the DM is now just changing the rules because someone knows how to zone their enemy, I'm going to call BS on that.

 

[Morrus]

And there's the crux of the issue, the battle is underway and if the DM is now just changing the rules because someone knows how to zone their enemy, I'm going to call BS on that.

Well, you have to do the work in advance rather than make it up as you go along.

 

[Whizbang Dustyboots]

Magical defense work best when there aren't people flying above you dropping huge boulders on your head at terminal velocity.

Which spell allows a mage to carry a boulder aloft and drop it? Fly won't do it -- and it certainly won't give you time to do it twice. (Especially if an enemy mage casts Dispel Magic on you while you're in mid-air.) What level do they have to be to cast it? And how many such wizards do you really think exist in the world?

Most D&D worlds don't have the magical equivalent of Green Lanterns running around in sufficient numbers to do what's being suggested here. The rare wizards who could pull off what you're suggesting are probably not interested in exposing themselves to hundreds of archers and who knows how many enemy spellcasters to pull this off.

Much easier and safer to just dominate someone else into invading, old-school.

 

[Jack Simth]

Which spell allows a mage to carry a boulder aloft and drop it? Fly won't do it -- and it certainly won't give you time to do it twice. (Especially if an enemy mage casts Dispel Magic on you while you're in mid-air.) What level do they have to be to cast it? And how many such wizards do you really think exist in the world?

It's a combination of spells doable by a Wizard-5. If you check the city generation tables in the DMG, there's quite a few of these in a generic D&D setting.

Fly and Invisibility on the Wizard, to get 200 feet up above the castle in question unseen.

Shrink Item on the boulder. Rock is pretty dense, and ten cubic feet of rock is HEAVY, dealing a hefty amount of damage to structures when dropped from 200+ feet up.

How it works:
1) Cast Shrink Item on a number of 10 cubic foot boulders well in advance (duration is days/level, so not an issue).
2) Get out of line of sight of the defensive structure, and be at least 200 feet away.
3) Cast Fly on yourself (1 standard action)
4) Cast Invisibility on yourself (1 standard action).
5) Staying at least 200 feet away from the castle at all times, go 200+ feet up, then fly over the castle.
6) Pull out one of your shrunk boulders, and hold it in your hand, facing downwards (or in a small net by a string, or whatever is needed for the particular set of rules your DM is using for having it immediately fall out of your hands when you hit the next step).
7) Dismiss the Shrink Item spell effect on that boulder.
8) Watch the boulder fall, as you look up the Falling Item Rules.
9) Move over a bit, and repeat from 6 until you're out of either boulders or targets.
10) Fly back to home base.

Can this be stopped? Yes. True Seeing won't do it (range limitation - 120 feet), nor will Arcane Sight (likewise). You pretty much either need See Invisibility up continuously (it has no range limitation - but it's tricky, as it's a relatively short duration spell for monitoring such things, and it's a personal-range spell, so it's hard to get on your soldiers anyway), or something fairly absolute that stops dropped boulders (like building your roof out of Walls of Force, per the Stronghold Builder's Guide).

But even if you can't stop it outright for whatever reason, you still expended some resources on the part of the opposing army to neutralize your fortifications, so they served a purpose, even if it's not an efficient one.

 

[Dandu]

Which spell allows a mage to carry a boulder aloft and drop it? Fly won't do it -- and it certainly won't give you time to do it twice.

I believe a spell that enables you to shrink an item would be best used to carry boulders.

(Especially if an enemy mage casts Dispel Magic on you while you're in mid-air.)

Yes, dispel magic can be a problem. That's why I highly suggest keeping distance from the target, or at least a ring of counterspells or something.

[quoteWhat level do they have to be to cast it? And how many such wizards do you really think exist in the world?[/quote]
Level 3 spell, so... level 5 wizard?

Most D&D worlds don't have the magical equivalent of Green Lanterns running around in sufficient numbers to do what's being suggested here. The rare wizards who could pull off what you're suggesting are probably not interested in exposing themselves to hundreds of archers and who knows how many enemy spellcasters to pull this off.

Actually, according to the DMG distribution for higher level characters, level 5 wizards aren't especially uncommon. Whether they'd be interseted in exposing themselves to enemy fire is an interesting question, but I figure spells like Protection from Arrows would help with that.

As for enemy spellcasters, who knows indeed! If they're common enough that you could have the large amount you implied dispelling the bombardier, then wizards capable of casting third level spells should be fairly common, thus enabling this strategy. If wizards capable of casting third level spells are rare, there is, of course, less to be feared with this strategy.

 

[Whizbang Dustyboots]

If you're equipping an army of level 5 wizards with rings of counterspells, you're spending far more resources on this than would be required to hire an insanely huge army of humanoids to do the same, with less accountability.

Your smarter enemy won't be using magical supergeniuses as super-catapults -- they'll be using them to infiltrate the command structure and wipe it out. You've destroyed their castle -- they've killed all your generals and taken the ruling family hostage, other than the ones they let "escape" who are under their control, in one way or another.

And you don't need an army of wizards equipped with expensive magical items to do it, either. The equivalent of an adventuring party could do it.