Wednesday, January 30, 2008

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 defendsers' 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, counterintuitively, 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...