Defenses in D&D

One of the wierd things about D&D is how the use of defenses actually works to the detriment of the defenders in a standard game of D&D. (Whenever I boot a game of Diablo for a half-hour break this occurs to me.) Here's what I mean: 

In the real world, defenses and strongholds are meant to bolster a weak party against a strong party. For example, castles were built to allow a small number of defenders to hold off a large army (for an amount of time, perhaps until an allied force arrives, or the invader runs out of money to pay his troops). The basic idea is that by channeling invaders down some narrow passage, you can fight them one-at-a-time, at equal odds or advantageously, instead at the skewed odds against all the attackers at once. 

Now, this assumes one critical criteria -- That the defenders are, man-to-man, about equal or stronger than the men in the attacking force. In the medieval real world, this is basically always true. 

But this key requirement is perfectly upended in the standard D&D game. Here, the general gameplay is for a very small number of PCs to be invading the territory of some sizeable hordes of evil beasts or minions, and the PCs are generally much stronger than most of the defenders they're fighting against, man-to-man. It's almost always desirable for the PCs to fight man-to-man if they can (they overpower most of the defenders), while it would be in the defenders' best interest to bring the whole weight of their numbers to play at once (they could surround, flank, and get many attacks per single attack of the PCs). 

And that's why, counter-intuitively, almost all the "defenses" and tactical terrain in a D&D game wind up working for the PCs and against the monsters. It's actually the PCs who want to restrict mobility and fight the monsters one at a time. It's the monsters who are hurt by not being able to move freely and pig-pile the PCs. 

The best possible case for the PCs is, usually, a single doorway where the toughest PC fighter can stand and chop down the monsters one by one. That's why smart PC fights wind up tactically with the PCs defending some narrow passage, and the native monsters acting the part of the attackers, getting mowed down as they try to wiggle through their own defenses. 

And that's one of the reasons why the canonical "warren of kobold tunnels" never ever works (in my experience), because kobolds coming one at a time against the PCs is actually the best possible thing the PCs could hope for. They're the ones who are outnumbered (and facing weaker opponents), and therefore want limited mobility in the fight. Defenses help the small party -- and in D&D that's practically always the PCs. 

How to deal with this in-game? Well, as a rationalization, you could say that standard stronghold/dungeon defenses do in fact keep out the hoi poloi (normal soldiers), and that's exactly why you need to send in extra-powerful PCs to root out the evil stronghold all the time. On the other hand, it argues for actual defenders arming themselves almost exclusively with missile weapons, and arranging defenses that allow the entire defensive host to rain down missiles on the attackers all at the same time -- perhaps narrow entryways that open into big spaces or courtyards which are basically firing ranges. A whole bunch of spread-out archers or missile-throwers can be the toughest thing for a standard PC party to deal with (assuming the archers have any kind of appreciable chance at punching through the PCs' armor, which is sometimes not the case).


  1. Sounds in some ways like you're invoking the legendary "Tucker's Kobolds" here, where the kobolds in question pretty much used logical tactics in the fashion you describe, and the PC's in that DM's campaign suffered for it.

    Another possible rationalization is the idea that many dungeons are older structures that are inherited/colonized by less sophisticated creatures than the original builders. The archetype being the Mines of Moria. Crewed by seasoned dwarf warriors, the complex is impossible to besiege, but a savvy dungeoneer might put the old defenses to good use against the rabble of slackjawed goblins that occupy it now. Could be an interesting take on the dwarven "stonecunning" ability to have them be able to notice useful defensive construction.

    I know that the squatters/inheritors model doesn't cover every possible dungeon scenario, but it catches some of them. It'd be different for a dragon's lair, or a lich's sanctum, or hell, even a hobgoblin community, since they're smarter creatures with tactical minds, and in the earlier cases, plenty of time to hone those defenses...

  2. After some recent playtesting, I'm more convinced of this thesis than ever. If a creature type makes its living in numbers (like a kobold horde), then its critical for them to be set in big, open spaces to use the weight of their numbers to their advantage.

    So now I'm seeing kobolds prefering a big cave/cavern complex where they can spread out, surround, pelt with missiles anyone who intrudes. (Antithesis of the twisty small tunnel model.)
    Maybe access corridors are guarded by a few unmanned traps. But other than that, any defensive portals would only work to the advantage of larger (less numerous) attackers. Maybe they use something like native hunters, lure foes into a big trapped open cave that serves as a missile-killing zone.

    The playtests I've done make a big open cave with a bunch of kobolds look a lot more interesting and fast-paced that narrow, bottled-up corridors.

  3. I have run into the same thing, although not with kobolds. :)
    How I have overcome the sheer power of a party of adventurers when storming a fortified position is the use of clever traps - not just any trap, which any self-respecting rogue spec can defeat; but natural traps that make those ideal corridors harder to stand your ground in and force you to keep on the move.

    One time my party even got sealed in by the enemy, they had killed so many it had clogged the corridor and they had chosen to defend a dead-end. The Orcs and Ogres they were facing decided to pile and pack the dead in as tight as possible and then mortar up the tunnel. Can you imagine that gruesome fate or at least the stench of decaying enemies?

  4. Wow, I must say that's diabolically awesome! Never would have thought of that...

  5. Kobald warrens should consist of tight entrances leading to a maze of tight, winding, cross-linking twisting tunnels, weaving around each other in three dimensions. The tunnels would be dug by kobalds, for kobalds. So they would be 3'-4' high and wide, at most.

    This means that most PCs would be crawling on their hands and knees, proceeding single-file, and only the PC in the lead would be able to see what was ahead. Missile fire would be impossible except by the lead character, and only by the smallest of devices (maybe shortbows, but no longbows, heavy crossbows, or slings), and rate of fire would be diminished as the characters are almost certainly firing from a kneeling position, very restricted motion to draw and knock, etc.

    There would be no safe path through the tunnels; the native kobalds would know by heart how to navigate them and how to avoid triggering the traps. They would regularly use all tunnels, so attempts at tracking would not be useful. All tunnels would be rigged with covered or camouflaged pits, triggerable cave-ins, and other devious traps. The kobalds would never present themselves to the PCs, except to act as lures to traps from a safe position. Finding the way out would also be nearly impossible, so the clock would begin ticking on exhaustion, food and water supplies, etc. Resting to regain spells and eliminate the effects of exhaustion should be ruled impossible while in the warren.

    The most likely outcome for most PCs, regardless of level, would be to be buried under tons of dirt and rubble, and die of crush or asphyxiation.

    If a PC or two ever did get to the actual kobald living space, they would find themselves in a vast low cavern, 6'-8' high at max, but stretching far and wide. The ceiling would be strung with nets that would be released by a simple tug on the proper knot (which the kobalds are intimately familiar with, but would take the PCs days to sort out.) The kobalds would be spread out around the PCs to minimize exposure to area of affect attacks. They would be armed with javelins, shortbows, pikes, man-catchers, and such weapons as are effective at keeping the foe at a distance. As characters become ensnared in nets and separated from their fellows, they would be immediately swarmed by kobalds. Getting oneself un-netted while a swarm of kobalds is piling on top of you, stabbing and biting would be virtually impossible; almost certain death. Spellcasters would have very little chance of ever getting a spell off without interruption in such a .

    AD&D Monster Manual says a kobald tribe is 40-400 individuals (which I take to be fighting males). In defending a lair, I would include an equal number of females, equally dedicated to fighting to repel invaders.

    I would map out only the living quarters, indicating only the several entrances to the maze tunnels. To navigate the maze, I would perhaps give a 1 in 20 (5%) chance checked each hour traveled through the maze (don't count time spent dealing with traps and skirmishes, only time spent actually on-the-move) to find the entrance to the living area.

    Invading a kobald warren, done right, should be a terrible experience, even for those who somehow survive. This is why kobalds are not extinct. They're nearly impossible to root out. They may be easily killed in small exposed groups while they're out hunting and foraging away from the warren, but no one in their right mind would actually go into a warren to clean them out.

    1. all good. However, if the players are mapping they won't get lost or need navigation checks to find their way back out.

    2. Depending on the edition of the rules, the PCs shouldn't be able to use shields (period), dexterity-bonus defenses, and potentially armor (any of it, at all, no really: one tight pinch and beefy Conan in front gets a strap caught in the tunnel). Plus the torches would be emitting smoke and threatening to ignite PC clothing during combat, laterns would shatter and spread burning oil, the PCs would get separated and confused during the slightest tactical movements (even 5' or 10' in combat could be overwhelming if the kobolds can pour in between two halves of the party at a Y fork). Honestly, the PCs should typically be absolutely annihilated in small, twisty passages if they're dumb enough to try them. At a minimum, a heavy amount of scouting should be required for surviving a quick in-and-out.