Military tactics vs. high-level spellcasters

[Baron Opal]

Say you've got an army of 10,000 men, most of them 4th level or less. And you want to sack a fortress that has 20 mid- to high-level spellcasters and say 500 soldiers. ...

Assume you have access to a lot of 3rd level spells, a fair number of 4th, and progressively less of the higher level spells, of different classes.

Oh, wait. What do you mean by "20 mid- to high-level spellcasters"? To me that means anywhere from 9th to 15th level. If you split the difference and make them 20 11th level wizards of varying specialties with a month to prepare, you're screwed. Especially if the army are a collection of 4th level characters. The army will get regularly hit with tunnelling earth elementals, succubus spies and air elementals carrying one-use items of cloudkill. Making sure disease takes root in the army would be a priority with a month to fester. There has got to be something you can summon to do that.

The only hope I can see is what limitations the summoners are under. They have the longest effective range on their spells. A strike team must impede or kill their summoners. Even then, it would be a tough nut.

"Game over, man! Game over!"

 

[Eccles]

'diminishing numbers of high level spells'?

Got any level 9 spells kicking around?

Summon Elemental Monolith.

Summon Unseen Servant.

Order it to give you a foot massage.

Sit back and watch the carnage on your crystal ball, and possibly record it for posterity.

(Alternatively, go read that bit from Sepulchrave's story hour, where one level 16 or 17 druid (Nwm) slaughters an entire army of thousands on his own, and copy it...)

 

[DM_Matt]

I've heard a lot of evil suggestions for dealing with the town, so here is a non-evil one (also assuming evil enemies) :

Werebear Plague

Spreading other diseases, lycanthropy, vampirism, wightism, wraithitude, etc is evil, but this one turns its victims into Lawful Good Uber-Beings, and is spread by shapeshifters. Get a few werebear infiltrators and you may be pretty well set (although the hange wont be exponential, bc afflicteds cant transmit).

 

[Eccles]

I should add - order the unseen servant to give you the foot massage.

 

[S'mon]

Oh, wait. What do you mean by "20 mid- to high-level spellcasters"? To me that means anywhere from 9th to 15th level.

Per 3e RAW "mid to high" means 6th to 15th, or at minimum 6th to 11th. It's true that 20 6th-11th Wizards probably can't destroy an army of 10,000 in one engagment. With a month of time though, defending their lands vs an invading army, they probably can at least cripple it. In fact 500 light cavalry skirmishers could probably cripple it, if smartly played/led! This whole thing as described is a suicide mission for the invaders.

 

[Delta]

Option 2: Treachery: The army is a feint. Hijack/purchase a ship scheduled to arrive at the fortress and load your primary assault there. I recommend swarms, spawning undead, diseased supplies, etc.

Option 3: Treachery: Trojan ship. Main army is a feint. coop several ships and get troops to the city. Wait until the wizards go to maim the main army and then gut the facility, paying particular attention to their labs, spellbooks, etc.

Option 4: Da bomb. All you really need is one big Earthquake spell to turn the fortress to rubble.

Option 5: mercenaries. It's a peninsula, see what kind of amphibious creatures you can hire to either harass shipping or launch a direct attack on the fortress.

I think these options 2-5 are really the best ideas I've read on the thread. The only hope is a hugely "asymmetric threat", some element of sabotage and sneak-attack that the wizards never even thought to defend or scry against. To do that I presume would take a genius-level commander, and could possibly only work once in the history of the world.

Granted that the mass army marching in formation would be practically suicidal. The most compelling insight I've seen in the thread is that in reality, an army of 10,000 would like not be able to storm the castle even without the wizards! That just tickled me pink.

 

[Kalanyr]

To thieve from Pratchett:

"What to Do When One Army Occupies a Well-Fortified Fortress on Superior Ground and the Other Does Not"
"Endeavour to be the one inside."

This doesn't seem like a situation you are likely to win with even odds let alone odds where they have high-level spellcasters and you don't.

Given that your goal is to eliminate it as a seditious stronghold (as opposed to some Blitzkreig strategy where you need to hold the fortress before reinforcements arrive), I don't see why you're in such a rush you don't grab some high level casters yourself before marching to your death, withouth them this seems like a suicide mission.

The best I can think of is to give an infiltrator an extremely contagious disease and send them to their death and hope the enemy fail their saves.

 

[Reynard]

Wizards need rest to recover spells. In the siege situation, in addition to cutting off supply lines, poisoning the water and launching diseased livestock over the walls, the sieging army should make constant sorties (that's how you spell that, right?) against the defenders, with just enough force to raise the alarms repeatedly throughout the night. Sure, you'll lose some men (send the mercenaries) but after a week, the wizards are going to be depleted of spells. Then it is time to rush the walls and bring that sucker down!

 

[Kalanyr]

The alarms trick will probably work once maybe twice before the Wizards start sleeping in shifts in quietened rooms away from the alarms. (Your spelling of sorties was correct).

Poison and Disease seem to be about it and thats assuming no Wizard gets the bright idea to teleport in a friendly cleric or bind a clerical spellcasting or spell-like ability using planar.

 

[Kaodi]

There is one option I can think of, but it is not pretty.

How many bone devils do you think 10,000 souls will net you?

Fear Aura (Su): Bone devils can radiate a 5-foot-radius fear aura as a free action. Affected creatures must succeed on a DC 17 Will save or be affected as though by a fear spell (caster level 7th). A creature that successfully saves cannot be affected again by the same bone devil’s aura for 24 hours. Other devils are immune to the aura. The save DC is Charisma-based.
Poison (Ex): Injury, Fortitude DC 20, initial damage 1d6 Str, secondary damage 2d6 Str. The save DC
is Constitution-based.
Spell-Like Abilities: At will—greater teleport (self plus 50 pounds of objects only), dimensional anchor, fly, invisibility (self only), major image (DC 15), wall of ice. Caster level 12th. The save DC is Charisma-based.
Summon Devil (Sp): Once per day a bone devil can attempt to summon 2d10 lemures with a 50% chance of success, or another bone devil with a 35% chance of success. This ability is the equivalent of a 4th-level spell.

They are everything the attackers need bundled into a nice, tidy package.