Mass combats rules

[Jack Frost]

Hello there,

I'm currently planning the continuation of a campaign, and I'd like it to have mass combats. It would be interesting to put the characters in a war.

The problem is, the only rules for such combat are the ones in the miniatures handbook. The rules in there are useful, but I have a problem with the attack of an unit. It says every single creature in the unit must make an attack roll. This is not practical in the case of having 20, 30 or hundreds of creatures in an unit.

I had thought about making one single roll for all the unit. It would be too simplist to assume it's the roll of all the creatures in the unit, so maybe I could modify it with a d100 to represent the variation in the roll within the unit or using some sort of Gauss bell... I don't know...

Do you know of any way to fix this? Any suggestion?

PS: I could solve this with a dice thrower that allows me to set a difficulty and tells me how many dices were over said difficulty, but I haven't been able to find such thing so far.

[Telok]

It might take some work but I ran across a nice "mass" combat system hack in a different game. I'll try for a rough translation of it to D&D terms. It isn't designed to make a rigorous simulation of masses of combatants, just something simple enough to run and give decent results.

Define groups of creatures as single creatures. Swarms already sort of do this.

Take whatever your base creature is (say the elf warrior from the MM) and figure out how big your group is. Now take the number two and start doubling it until you get a number just below your group size (take powers of 2). For example you have a group of 40, so (2, 4, 8, 16, 32, 64) you have five doublings to get up to around 40. These are sort of like "swarm levels". The group had HP equal to the HP of the base critter times the number of critters in the group. It gets a bonus to hit and to Will saves versus fear equal to it's number of doublings and a penalty to AC and to Reflex saves on area of effect stuff equal to the number of doublings. Every time it does damage it does the critter's normal damage times the number of doublings. Every time it reaches half total HP it shrinks and becomes a group of the next size down. When it reaches one doubling you can treat it like individuals again, if it reaches 0 HP then the group is destroyed but the number of excess individuals is still wandering around demoralized and sad.

So take 40 elf warriors, five doublings get you to 32 and you have 8 extra elves floating around. The group has 40*4=160 hp, 15-5=10 AC, a +6 Will save vs. fear, a -4 Reflex save vs. AoE, attacks in melee at +7 for 5d8+5 or at range at +8 for 5d8. When it gets down below 80 hp it becomes a four doubling group with 20 elves in it. If the group sucks a maximized Cone of Cold or something that reduces it to 0 hit points then the group is broken but the extra elves are left running around (probably running away).

[Jack Frost]

The system you mention is very practical. I'll consider it for my campaign. It could have the effect of commanders of the miniatures book (+ some house rules). A drawback it has is it doesn't consider player characters too much :(

[flappeercraft]

I'm pretty sure there is a D&D compatible system called Battle system but I think its for 2e but it could be updated with some work.

[Khedrac]

I'm pretty sure there is a D&D compatible system called Battle system but I think its for 2e but it could be updated with some work.

BattleSystem was the 1st Ed AD&D system, I think it got updated to 2nd Ed but I am not sure on that. It was also more of a miniatures game than a large army game. I have no idea how well it would convert, but I suspect badly.
WarMachine was the BECMI D&D system (Companion book and Rules Cyclopedia). This was very much an army combat game and I think it might not be too hard to convert!
The Miniatures Handbook has miniatures rules for 3.5-based combat, but I agree with the OP about how they are not what you want.

However, that you probably want to do is read the 3.5 book Heroes of Battle, which has rules and suggestions for the PCs in a battle, which is a very different thing to rules for army combat.
My memory says that one of the suggestions is that you pre-define how the battle will go (unless the PCs are commanding it, you really don't need a system to model the conflict); but then, when working out what the PCs will encounter during the battle, also work out how their efforts can effect the overall outcome - anything from change a defeat into a rout or into a narrow victory. Alternatively the battle may always go one way, but the PCs get to stop their commanders dying or ensure that the enemy commanders die - it may not make a huge difference to this battle, but has a massive impact on the aftermath.
This gets the PC far more involved in battle and allows the DM to plan the campaign more coherently.

[neriractor]

There is a pretty good 3.0 Book called fields of blood that may be to your liking, is mostly about running a kingdom but the combat system is pretty nice.

[hifidelity2]

We used a system called Reaper

Basics of the system is

Everyone in a unit has a percentage chance to hit say 15% (elite units have a higher percentage etc)
if (say 20 men in a unit) then that gives you 15% x 25 = 375%. Each 100% is 1 auto hit (so 3 in this case) with a 75% chance of a 4th hit. Tis means you only need to roll 1 die for the unit
Each hit has a percentage chance to kill the opponent (this is based of the weapon used v the armour of the opponent unit)
e.g. in the above assume a 50% chance to kill. If we assume the 4th hot missed then this gives 3 x 50% = 150%. Again each 100% is a kill with a 50% chance of a second kill

Tis means that for large units you only need to roll 2 sets of die.
The chance to hit, chance to kill can all be worked out in advance

In the rules there were bonuses for charging, formations, cover etc but they just modified the percentages

[Vaern]

When my bard picked up leadership, we joked for a while that eventually we'd have to start fighting battles on a Risk or Axis and Allies board.

[Telok]

The system you mention is very practical. I'll consider it for my campaign. It could have the effect of commanders of the miniatures book (+ some house rules). A drawback it has is it doesn't consider player characters too much :(

It ought to work ok with characters, it pretty much just turns the group into one creature to fight. As I was thinking about it later I'd also add that all groups go simultaneously at initative, pole arms get two attacks on the first round of engaging with an enemy, and maybe that the hit/ac modifier ought to be twice the number of doublings.

You would have to iron out spellcasters, there's some complexity there if you use anything but unmodified damage and healing spells. Obviously it leaves out tripping and grapples too. But it's a starting point for a pretty simple mob vs. mob combat that allows for PCs to interact mostly normally.

You know, it just occurred to me, a fighter who throws out a 40 damage attack would down 10 of those elves.

[Calthropstu]

Try looking at the pathfinder rules for this... it seemed fairly well done actually.

They can be found here (http://paizo.com/pathfinderRPG/prd/ultimateCampaign/kingdomsAndWar/massCombat.html)

[Pugwampy]

I had thought about making one single roll for all the unit.


Its the easiest .

Mass combat is awesome fun but your average book rules hinder more then help .
One roll for each combatant or possibly even groups .
High/Low roll . Winner lives , and loser dies end of story . If you want to be fancy give the winner a dice roll of damage .

Let players fight normally whom ever they are engaged with .