How do you run mass combat?

[Gaiden]

This is probably going to be the least helpful because of the inordinate amount of time it takes preparing, but for what its worth, this is what I do:

I first take a look at the mass combat from the perspectives of the PC's - after all, what happens around them is irrelevant - it is only what happens to them and what they do to those around them 1that really matters mechanically.

Mass combat is all about placement. A battlefield 10 football fields in length is largely irrelevant to the PCs. Barring lightning fast monks and specialist evokers, the majority of what happens can be pinpointed to precise locations on the battlefield (perhaps 300' radii areas).

So, I first try and predict what the PC's will do and how they will do it. Knowing the details of your character's PC's is crucial at this point. You have to be able to predict for entangles, webs, fireballs, blade barriers etc. After I have spent days (this is usually how long it takes to really get an idea of the different possibilities), I plan out the different scenarios as simple encounters. So perhaps the group of PC's will go against a battallion of mounted goblin warg riders, or perhaps a legion of mindless undead, etc. Maybe there will even be a grand melee mixing mounted goblins, various undead legions, and ogre shock troops. Whatever the case may be, I try and predict which encounters matter. I plan those as normal.

Now here comes the fun part . All of the other stuff, I roll out ahead of time to see what happens. For this you need a very big spread sheet. So I organize the spreadsheet by groupings according to the respective groupings in the army. Then round by round, I determine actions and outcome. I have all of it planned ahead of time so I can give description to the players of what is happening around them while also making the battle real for them.

Now, this method SUCKS. It takes absolutely forever and one small miscalculation on the PC's actions and much of the planning is wasted. Up to this point, I have not miscalculated. (I have also planned several different scenarios if I wasn't sure which route my PC's would choose). The only thing that is at all good about this method is that I feel it is the most true to the D&D mechanics. Of course its not a true mass combat system because I haven't actually done anything mass combat-like.

The first time I tried this was when I had a 19th level necromancer assault a college of wizardry. (Yeah, tell me about it - all that spellcasting was ridiculous). The necromancer was actually an invited speaker and in the auditorium he let loose (absolutely wasted all of the students). There were two PC's - both visitors to the college sitting in on the lecture. The auditorium was basically a huge amphitheatre with floating tensor's disks at different levels (serving as seats) and a few "special" disks for the higher ranking members of the school that were telekinesis-able (if that is a word). I think I had some 200 odd students and ~30 instructors. There was absolutely no pretense for attack. The necromancer had at one point been an instructor at the college and was on good terms with the current faculty so no one expected an attack from him.

The first thing he did was cast a vile spell from BoVD (the 1st level spell that causes the victims eyes to explode a spray of acid). He had metamagicked it (from feats from Dragon) to take an emanation AoE and extended the range so that it filled the room (I forget if it wound up being the equivalent of an 8th or 9th level spell after all the metamagics). I gave him surprise to everyone but the PC's. So I pretended the PC's weren' there to begin with. I rolled saves for all 200+ audience members (as well as the other key note speakers) and then determined how much damage each person took form the various sprays of acid. I figured which mages would have contingencies to teleport them away in the event that they were attacks, which would have globe of invulnerability contingencies, etc. After resolving the first round, I determined the order of actions of each of the surviving NPC's and then made a spread sheet detailing these actions on a round by round basis.

When I ran it, the players were absolutely horrified at the description of everyone's eyes exploding in a spary of acid that melted the faces of themselves and everyone around them. It was beautiful. (They were conveniently in the AoE of a globe of invulnerability ). After the first attack, most of the students were dead (conveniently) and I really only had to deal with 20 to 30 NPCs, most of which were very low level and simply wanted to flee. So you could say that I kind of cheated and that this wasn't really a mass combat situation. But my above system worked pretty well for determining the outcome and didn't slow down game play at all (the only thing that took time were my lenghty pre-prepared descriptions).

 

[TheAuldGrump]

I use 2 different mass combat systems depending on the number of combatants and scale involved:

- Mongoose's OMCS v.2 (Open Mass Combat System, version 2) for large skirmishes, between about 30-300 combatants.

- Eden's Fields of Blood for anything larger (armies, really).

So in your example above, I'd use the OMCS 2 rules. You should get some results you'll accept out of this (as it does take into account levels, etc, and is easy to quickly modify to give you game mechanic bonuses and results that you want/expect).

I also use OMC v.2 - the integration with both siege rules and with the Open Naval Combat system in Book of the Sea makes it too handy not to use. I have been sporadically working on a conversion so that I can use it with OGL Steampunk..

The Auld Grump

 

[ThirdWizard]

I decide the outcome based on DM fiat.

 

[Bojangles]

There is no good way to run mass combat in DnD. The system jsut doesn't support it. I tried to run a bastardization of the Slaine system where all combatants are grouped into a unit that are alike (footsoldiers, calvalry, archers, etc.) and the HP of the group is the # of people in it +10% per point of con bonus and doubled for each extra hit die. The group attacks another group doing damage = weapon damage + average strenght modifier + number of people. They have an AC and attack bonus of the average amongst them.

Its ok but misses out on a lot of little things. Also has a will save system against breaking and fleeing but i didnt use that, I just played that by ear.

 

[Jack Simth]

Was in a game once where the DM was running a mass combat with 40 PC-Hired mercenaries vs. about 20 or so defending bandits (mostly) by individuals. He decided it was taking too long, so I suggested a quick ad-hock complexity reduction:

Instant Mutual Anhillilation.

When a Merc ran into a defending bandit, both died. When a defending bandit ran into a merc, both died. When a PC took a swing at a defending bandit, roll to-hit and roll damage; if a PC was close to the defending bandit horde, a bandit or two would take a swing at the PC (and roll normally). It worked out fairly well, for a completely ad-hock system. Eliminates the PC's ability to do tactics (e.g., lure melee opponents into a room with lots of archers lining the walls) but it cut down on the paperwork. Likewise, it would need adjustment based on differences if one side was more robust than the other, but for the situation, it did it's job. (Fortunately, the PC hired mercenaries outnumbered the defenders.... I had no idea of the relative numbers when I suggested it. Honest!)

 

[S'mon]

For skirmishes where there's lots of fighting around the PCs, I've used a simple system where each round, each NPC rolls a d6 (or a d20) and kills his foe on eg a 6 or an 18-20. It's most suitable where the PCs are at grunt level, of roughly similar ability to the NPCs, and you don't want to waste time resolving NPC vs NPC but do want to give a sense of the ebb and flow of the surrounding battle. Here's one, slightly complexified version of this:

>>Every figure (individual or squad) gets an Attack Rating, which is the base number (or higher) they need to roll on a d20 to kill a typical opponent (so lower the better), and a Defense Rating, which is the number added to the opponent's AR, so higher the the better.

A typical human warrior (AC 16 ATT+4 hp 12 average damage 6) has Attack 16 Defense 0, that means they kill a similar foe on a roll of 16+0 = 16 or higher on a d20 each round.

Sample stats:
Human warrior: ATT 16 DEF 0
Human Knight: ATT 13 DEF 3
Orc ATT 15 DEF 0
Dwarf ATT 15 DEF 2
Ogre ATT 8 DEF 4 <<

That makes it sound a bit complicated, but the simple idea is that if in D&D it takes on average 3 rounds for 1 NPC to kill another NPC, give them a 1 in 6 chance per round - eg roll a 6 on d6 - and you get reasonable results. If it takes on average 2 rounds, give them a 1 in 4 chance, and so on.

 

[Inconsequenti-AL]

I mostly cinematic it. Will describe the battle around the PCs, and how their interactions affect it.

To randomise: I give each side an overall rating - basically factoring in plans the generals have made, troop types, terrain and PC actions. I'll make opposed rolls between the sides. Winner is gaining the upper hand. Margin of success indicates by how much. Might make things more or less difficult depending on how hard or easy the PCs are finding things.

Generally this works out pretty well. Quick, dirty and keeps the PCs at the center of the action. Which is what I'm looking for...

S'Mon - I really like your system. Makes a lot of sense for 20-30 a side encounters. Think I might be ripping that off.

 

[The Souljourner]

We did something similar... used a Warhammer table and miniatures, but we rolled each attack individually. For movement you kinda drop the whole squares thing and just say 5 feet = 1" and be done with it. If your players include at least one spellcaster, you almost have to do it this way. You can't take into account fireballs etc otherwise.

It actually didn't take forever. Sure, it took 4 hours or so, but it was damn cool and well worth it. We had like 200 people defending a walled town with the party versus an oncoming horde of orcs and other meanies. It's not really that bad if you have plenty of dice (and what roleplayers don't?) You roll like 20 dice at once to hit, roll half that many for damage... Keep a bunch of graph paper handy to keep track of hitpoints.. no problem.

Most mass combat systems take all the fun out of the game, and definitely don't do well at letting the party have a personal and tangible impact on the battle. Do it the hard way... it takes some time, but it's well worth it.

-The Souljourner

 

[irdeggman]

There is also the BRCS at Birthright.net and of course the upcoming mass combat system by WotC should be something to look at.

 

[Nebulous]

I vote for Grim Tales. It's really great. There is the option for letting the PC's have heroic input. I think there are rules for getting close to the "leader" of the enemy unit or war, and then the PC's have 10 regular combat rounds to dispose of him, or otherwise they are swept away by the tide of battle. So i think it would work if you utilized the mass combat rules for general battle (1 minute rounds) and then zeroed in on specific, heroic events in 6 second rounds.

Free Companies for Conan d20 is also good, but not as useful if you don't use the world setting.


Cry Havoc was WAY too complicated.


EDIT: Grim Tales is good but it has some holes and is vague in some areas. It will require some important DM decisions because questions will come up that the pdf doesn't address.