How do I quicken / sum up larger (but not army-scale) d20/DnD3.x combat?

Question

I'll be rather specific:

Imagine you have five lv7 characters (in DnD3.5), a bunch of their followers (skeletons raised by their priestess and whatnot), and they're facing about the same number of opponents who pose a balanced (and, let's say, quite matching) challenge to the group.

In what ways can you speed up / sum up and get the result of the confrontation? The story would benefit a great deal from omitting or at least speeding really up the IRL hours long dice-rolling. (Yes, keeping track of which friendly skeleton hit which opposing skeleton is truly tedious, yet their presence in the story is both inevitable and good.)

(Side-question: Is there maybe a free app online that can intelligently play out such a skirmish?)

Answers relying on mechanics from, and/or usable in other d20 products are welcome.

Answer 1

I developed a quickie "mass" combat system for my Pathfinder campaign because the PCs kept having groups of pirates or whatnot on their side. I read some of the existing mass combat rules in various D&D books (mostly third party) but they were always either too complicated for what I wanted or they integrated very poorly with character level action.

Here's my ruleset. The general approach is to combine units of like creatures in batches of 5 or 10, give them one attack with an attack bonus = 1/2 the number of creatures and a damage bonus = number of creatures, and kill off individuals in the unit as the whole unit takes increments of enough hp in damage. It's quick and easy and integrates perfectly with PC level actions. A couple more details re: area effect and done!

Example: 10 pirates with +3 to hit, 1d6+2 shortsword damage, and 22 hp become one unit with +8 to hit and 1d6+12 damage. They can attack another unit - or interact with a PC on a one on one basis. I then draw 10 boxes that are worth 22 hp each, and basically round - if someone does somewhere around 10 points to the unit it's one diagonal line through, do around 22 it's X'ed out. If another unit or a PC kills some of them, the hit/damage bonus goes down, so eventually it reduces to "one guy of normal stats."

If you don't want any alternate rules, then you can just do some dice shortcuts. First shortcut - have mooks do average damage instead of rolling damage dice. Second shortcut - roll one die for several mooks' attacks at once. Third shortcut - don't track mook hit points precisely, just rough it to a number of "good whacks" they can take (one, two, three...) Past that you get to changes of the scope of my ruleset, before you go to big Mass Combat Rulesets (tm).

Answer 2

Any large battle can be reduced to a statistical model.

It is fairly trivial to calculate the average damage (factoring in the to-hit) of each NPC per round.

\$\left(1 - \frac{\left(EnemyAC - ToHit\right)}{20} - critChance\right)\times averageWeaponDamage + critChance\times critDamage\$

There are two levels of useful granularity here:

1. Tactical

   Tactical granularity is when you have each enemy on the battlefront deal its average damage to an enemy it can reach. This naturally allows for the impact of flanking and archery upon battle lines. However, it does require keeping track of the HP of each soldier. While there is some element of chance lost by removing the dice, it is effectively a wash as chance will effect both sides equally. If players are commanding one side of the battle, this is the way to allow the consequences of the players tactical decisions to be felt. If they've stationed archers, kept a reserve, and/or tried for a flank, removing the die-rolls but keeping the unit-level simulation is the way to go.

2. Operational

   Operational granularity allows for quick force versus force resolution. Assuming both sides have equal tactics, simply take the average damage of each unit, multiply by the number of units and apply it to the other side. The other side loses damageTaken/averageSoldierHP soldiers. Having enemy generals roll for initiative is a way to keep chance as an element.

For interesting mass combat rules, I once again recommend K and his Races of War wherin he removes elements from 3.5 that make him sad. You may also want to look at the book Heroes of Battle which also contains mass combat rules.

Answer 3

A single die roll.

Once I tried GMing a game system that was quite cumbersome when combat was PCs versus the same number of enemies. At one point in the adventure the enemy party was 20-ish strong. Everything broke down. I panicked.

Then I began using a single die. A group of five attack one of the characters. I grab five dice and throw them on the table. "Two of them hit you, but none bypass your armor. Write up 11 points of damage." Crude, but we all liked it.

More concretely, I used a d6. They are plentiful and resolution is low (quick for the GM to decide on a DC). I set the base chance to hit at 50%. Consequently, a +1 or -1 modifier is given only for significant factors – combat training, enhancement magic, improvised weapons.

However, important exchanges (for example, all character attacks) are still made using the full game rules.

Answer 4

Here's a system my current DM came up with, which has been great fun:

First, some assumptions I hold. The first is that the PCs and the Enemies are the interesting parties in this conflict, not the hodge-podge of friendly NPCs, cohorts or minions. We don't go into combats to hang around and let the DM roll dice against himself.

Secondly, battles in D20 are slow and complicated enough as it is, and we want to inject as much flavor and fun into them as possible, not just slug it out to inflict maximum damage as quickly as possible.

With this in mind, our DM opted, in a rather large battle with a pack of mutated bulettes where we were helped by about 15 soldiers and scholars, not to have those NPCs actually have their own initiative scores and attack rolls - this was our fight, and we didn't want to take the narrative focus off of that. What he did do was allow us to use them as helpers for any actions we want to take. If it was cool, they added bonuses.

For example, one character might shout out to the soldiers to fire their crossbows at the bulette. He rolled a Diplomacy check, had a good roll, and the DM ruled that their half-hearted bolts, while not harming the bulette directly, distracted him enough to offer the character flanking while he attacked. Another character might use them for cover. And at the battle's climax, another character called up all the NPCs together, along with a casting of Create Water to turn the ground to mud, to serve as assistants in a massive Bull Rush maneuver to push the giant bulette into the lake.

This served several purposes. The first, of course, is to minimize the time spent doing actual combat for boring NPCs. But importantly, it allowed the players to let their creativity run loose, and do bigger and cooler stuff than we would do normally in combat.

Answer 5

Typically what I've done is any situation that involves a PC, roll that out. Handle it just like you would an orc attacking the whole party.

If it's NPC vs. NPC, hand-wave it. I typically will roll a die for each side (depends on tactics, odds, etc), and that is the number of NPCs that die that round. If a side gets a significant number advantage, either their die goes to fewer faces or the opponent's gets more. True, it lacks realism, but it WILL speed up the combat significantly.

Another trick is party initiative. I find that in the really big combats the gm has too much on their minds, and sometimes will forget a player/npc. Party initiative combats this since everyone goes at the same time.