Manning the Keep on the Borderlands are 244 combat-capable individuals. Broken down, this force is comprised of 52 Heavy Infantry, 120 heavy infantry who are also equipped with bows & crossbows, 24 light infantry, 12 heavy cavalry, 18 medium cavalry, and 18 Auxilia/militia (individuals who are capable of combat & possess equipment, though are not part of the fortress’s standard ‘fighting force’, including a low-level mage). Among these 244, there are 8 commanders, 3 ranking clerics, and an elf, who, by virtue of their equipment, I’ve included in the total of Heavy Infantry.
An excursion to the Caves with 2/3s of this would be a fighting force of 162.
Let’s figure the makeup of this group:
All 30 cavalry
5 commanders (1 captain, 3 Corporals, 1 Sergeant)
2 Clerics (The Curate & Priest)
28 Hvy Inf
18 Lt Inf
The total fighting force of the Caves of chaos consists of:
262 Evil Light Inf (59 kobolds + 1 chief, 34 orcs + 1 chief, 41 goblins, 29 hobgoblins, 13 bugbears, 20 gnolls, 16 zombies, 32 skeletons)
70 Evil Heavy Inf (1 orc chief, 1 goblin chief, 9 hobgoblins + 1 chief, 9 bugbears + 1 chief, 13 gnolls + 1 chief, 23 zombies, 9 evil priests, 1 minotaur, 1 ogre)
15 Evil Bowmen (various races)
There are 11 Entrances/Bolt-holes in the valley. Because of the number of entrances, it would be difficult to adequately cover any single hole or group of holes if a concentrated attack were made. On the other hand, any group attacking from a hole that was being covered by archers would incur a good deal of injuries.
The “Keep” forces, though outnumbered in terms of both men and hit dice, have the massive advantage of firepower, with 80 bowmen to the cave’s 15. Additionally, these bowmen aren’t light archers; they’re heavy infantry who happen to have bows & crossbows. In the scenario I described, the Castellan stays back at the keep, but if he came along, he adds a major asset to the Keep’s force, in that, as a F6, he is stronger than either the Minotaur or Ogre.
There are a few strategies the Keep forces could employ. They do not have the numbers to lay an effective siege; without their full number available to repel an all-out assault from a particular entrance, the Keep forces could quickly be routed. Careful planning might allow for a few entrances to be temporarily blocked with fire or debris, but the number of entrances makes ‘smoking out’ the cave’s inhabitants untenable, at least for a force the size that the keep could field.
Rather than have teams cover each entrance, the Keep forces might setup a “zone defense” around the valley.
North: 30 bowmen, 4 lt. inf. 6 Hvy. Inf. 6 Med Cav, 6 Hvy Cav
West: 20 bowmen, 10 lt. inf., 4 Hvy Inf., 6 Med Cav
South: 30 bowmen, 4 lt. inf., 6 Hvy. Inf. 6 Med Cav, 6 Hvy Cav
Strike Team: 10 Hvy Inf (5 Acolytes, 5 Men at Arms), The Curate (C5), a Captain (F3), and Elf (E3).
The three “zone” forces would be covering the entrances on each side of the valley, with the Western force (which is covering the fewest entrances) able to move quickly to respond to any sudden foray from the Caves. The valley is too steep for cavalry to effectively charge anything coming out of the caves, but they would be able to speedily move to fill in a defensive gap should one arise, and pursue any eastward fleeing troops.
The strike team would act as the stick to poke the hornet’s nest. They would not go particularly deep into the cave, engaging only in probing attacks. The strike team would shortly be followed by a group of 4 lt. and 4 hvy. infantry to the mouth of the cave. Their purpose would be securing the strike team’s escape route, assisting with extraction and alerting the rest of the Keep’s forces to any sudden change in the tactical situation. Unlike a heroic party, set on exploration, plunder, and systematic clearing of the cave, the strike team’s objective is to draw out the demi-humans into open combat. The idea is that the cave’s inhabitants would not be able to effectively respond to a succession of short attacks without entering into a full, fortress-wide defensive stance, or bring a greater force to bear against the Curate’s shock troops, which would lead the counter attackers into an ambush.
If the cave assumes a defensive stance, it will focus on dealing with the Curate’s troops. After meeting resistance, the Curate withdraws and attacks another entrance. The inhabitants may think they are under attack from a larger force, allowing the Keep to lay a more effective siege. Or, if they understand that there is only one group of troops they are preparing against cave-wide, the continual shifting of resources will hamper the Cave’s ability to mount a defense against the Keep’s full force. As needed, fresh troops can be supplied to the strike team from the Zones, which will serve to create an illusion to the group’s “invincibility”, necessitating larger concentrations of demi-human forces within the caves. I figure with the whole caves mobilized, non-combatants in danger from intruders, eventually something has to give.
This could be a long process; the strike team probably won’t be working 8-12 hour days, but rather 3-4, returning to a “zone” for rest and resupply before diving into another cave. Additionally, this team’s secondary role would be setting fire to foliage near the cave entrances, particularly H, A, G and E.
In a pitched battle, with both sides out on the open field, the fight would be fairly evenly matched. The main reason for this, of course, is the superiority of ranged weapons, giving the Keep’s forces maybe 2-3 rounds of missile combat prior to the start of melee. It would be easier to judge if I’d also taken into account the total Hit Dice for each side. Still, I have to give the edge to the Cave’s forces. Sure, they have a lot of 1/2 HD Kobolds, but they’ve got a lot of 2-4 HD monsters, too. If the Cave’s forces make their morale checks after suffering about 80 or so HD of losses to arrow fire, things could get a bit dicey. Though they’re well equipped, just about all of the Keep’s troops are F1.
This “open battle” scenario also assumes that the Caves have left behind only non-combatants. If, like the Keep’s forces, they only fielded 2/3s of their force (just over 200 troops), the Caves would still significantly outnumber the keep’s troops. How well the Keeps archers performed would make or break the outcome for either side.
Of course, neither side in the Borderlands has an incentive to face the other on an open field. This does not mean, however, that the situation is the strategic stalemate that it at first appears to be. Unlike any attempts to strike against the Caves, an attack against the keep would be doomed to failure. The forces of Chaos are the real underdogs here. Again, the preponderance of archers and presence of both ballistae and mini-catapults makes an attack on the Keep untenable. Unless an outside force of large numbers nowhere found within the module appears out of the east, the Keep on the Borderlands is here to stay, and it is the Caves whose days are numbered. That’s not to argue that the Caves’ presence does not make the borderlands unsafe for those travelling east outside the Keep, merely that its threat is overstated. The Caves pose no real threat to the Keep or any lands to the west of the keep.
This makes the Keep a key strategic importance, however. The Keep somehow falling to the forces of Chaos would be a far more significant shift in strategic balance than the cleansing of the Caves. The Caves, if anything, are a civilian target, more a town than a fortress. Its presence does not exert the same influence as the Keep. Were there instead a small castle inhabited by these demihumans, there would be a bit more parity in the region. PCs can easily invade the caves, though demi-humans cannot realistically access the Keep.
Keep on the Borderlands makes an interesting scenario for an “Evil” campaign. Instead of playing humans tasked with removing the nuisance of a small underground demi-human town, Borderlands offers the opportunity to play demihumans who are facing an existential threat from the presence of the Keep and its Adventurers who would set out to hunt them for sport.