Quick and efficient mass combat system.

[alhoon]

Here is a quick and efficient combat system that I devised. It is quite simple and most of the time works correctly. Of course there are exceptions and the DM should use common sense when using it.

It is NOT a mass combat system devised in order to turn a D&D game (or Ravenloft game) to a strategy game. It is more or less a quite accurate tool for the DM to quickly see how for example the Unit lead by the PC party fares in a battle.
Or even better, so the DM could let the dice quickly decide how the battle progresses while he concentrates his attention on the players actions.

So here it is:

1> First you calculate the Equivalent Level of each unit involved. I.e A group of 30 1st level human warriors and 4 2nd level officers is EL 9.
A group of 200 1st level human warriors, 10 3rd level officers and 4 6th level captains is EL 14

2> Calculate Battle Rating for each group. The BR starts as ELx2 + modifiers. Each condition the DM thinks is favorable/unfavorable gives a +1/-1 to the BR of the group.
I.e if the group has EL 14 and is:
Attacking the enemy from an ambush (+1) and their leader is a great strategist (+1), fighting within sight of their homes (+1) in bad weather (-1), tired from a long march (-1) the total BR is 14x2 +3 -2 =29

3> Roll initiative: Each group rolls for initiative, using the average (or better median) initiative bonus of the group. For example if Group A is elven soldier all with Dex 12 - 16 then the average initiative bonus is +2

4> The battle: The group that goes first decides a target and attacks. Roll 4d6+ the group's BR vs a DC of 10+the enemy's BR. If the roll succeeds the target's BR is reduced by 1. The target usually retaliates immediately after the attack using his new BR.
Proceed with the second group in the initiative order etc.

5> End of the battle: A group that cannot efficiently keep on the combat (i.e needs 22 or more in the 4d6 roll to cause damage) is effectively beaten. Remember that if the BR drops by 4, half the unit's soldiers are dead, captured, dying or otherwise neutralized. Remember also that Soldiers usually flee losing battles instead of fighting to the death. They may join other groups or run for the hills.
As the DM you should decide what happens.
For example a group of humans defending their homes may try to abandon their positions and flee to join another group of defenders, rising its BR. If they have nowhere to die, they may fight to the death. On the other hand, if the attackers lose half their numbers (i.e their BR drops by 4) they may decide to retreat.

[alhoon]

Special rules:
- If a unit disbands/retreats while engaged in melee with another group is subject to an attack (like an attack of opportunity) but doesn't retaliate.
- A unit that can't harm its opponents just receives damage without retaliaton or attack! I.e a group of 100 humans without silver weapons against 15 werewolves do NO damage. The DM of course could rule that if the creatures in question have low DR that the unit has some chance to overcome it, applying modifiers accordingly.
- A unit that holds the terrain after the battle, restores about half its fallen. It may decide to show mercy and restore half the enemy's forces too, or save them and capture them. They may decide to kill the wounded.
- Each round of the battle doesn't have a fixed amount of time. Each round of battle between a group of 35 humans and 9 ogres may take 4-5 rounds, while a round of battle with 15000 combatants in each side may take 1-2 hours!
- Remember: BR -1 is about 15% casualties, -2 is 1/3 of the unit in casualties, -4 means 50% of the unit are dead/captured/wounded, -6 means 2/3, -8 means 75%. The winner usually manages to heal 25-50% of its casualties.
- A group that can't reach its enemy is considered unable to attack/retaliate. I.e 100 soldiers without bows are powerless against 30 harpies with bows.
- The DM may rule that the group gets a "free" attack against an enemy if the unit has ranged weapons and the enemy doesn't as they pellet arrows/javelins towards the enemy as he approaches.
- If the PCs are involved and do their part, calculate their EL with the group. If they do exceptionally well, increase their EL if they don't use their powers/don't get involved much, reduce their EL.
I.e a 7th level wizard using a couple of fireballs and a scroll of fireball, is doing his part.
A 7th level wizard that uses a magic missile spell and miscalculates the fireball getting only a couple of soldiers missing the leader, and then is downed by crossbowmen, is not doing his part.
A 7th level wizard emptying a fresh wand of fireballs on the enemy dealing death like the fist of God, protected by "protection from arrows" and three rows of pikemen so none can harm him, is doing more than his part.

Clarifications:
- If the PCs do something worthwhile in the battle like killing the enemy general or his three death knights, or even manage to rout/destroy an entire group of soldiers don't be affraid to add modifiers in the BR or even reduce it.
I.e if the PCs manage to kill the three Death knights leading an enemy group with EL 13, and the CR of each DKnight is 8, then the EL of the group immediately drops by 2. The DM may further decided that the BR drops 5 instead of 4 since the enemy is demoralized!

- I propose 4d6 +BR instead of the usual d20+BR because the 4d6 have a range of 4-24 and most importantly a bell curve, meaning that it is more probable to get a results around 14 than say 5, 20 or 24.

[ScS of the Fraternity]

If you're going to use DC, shouldn't you be using the D20?
That would keep the rules more consistant with the rest of D20 rules.
Also, do you have a way of calculating causulties?

[Snake]

Hmm. I like this. Might just have to use it.

[alhoon]

If you're going to use DC, shouldn't you be using the D20?
That would keep the rules more consistant with the rest of D20 rules.

d20 involves too much randomness ScS. As I have said, I playtested it. 4d6 uses a bell curve which gives more results closer to the average (14) than towards the low/high end (4/24).

Using a 1d20, a group of 30 ogres managed to kill/drop unconsious 10 out of 30 Hill giants just because they were rolling high! I calculated chances using statistics and what I thought should be and after research I decided that the 4d6 is the best roll.

PS. I'm studying for my Master in Geostatistics and I have studied how to research such things.

If you decide to use d20, then get ready for some weirdness, not too much to be unusable, but quite much.
Also lower the DC by 5. I.e If the attacker rolls 1d20+BR the DC is 5+target's BR.

Also, do you have a way of calculating causulties?

The fairly easy way is as I proposed:
I.e BR-4 is 50% neutralized, BR-6 is 2/3, etc. Winner cuts casualties by half.
For example:
After a brutal battle Army A (initial 1500 soldiers, BR -3 in the end) manages to beat Army B. Army A now has 600 as casualties (BR -3 is 40% casualties). Since they held the battlefield they can help the dying (i.e those between 0- -9 hp) so they could in a few days restore 300 of their fallen.
The rest 300 are either dead or captured by Army B.

Complications: They are a lot, and I admit that I would like help here.
- Army B consists of beasties that do 2d6+10 damage. I.e The chances of dying outright, instead of hovering on death's door are far larger.
- Army B actually consists of countless kobolds that do 1d4-1 damage. Chances that you stabilize at -3 to -4 hp are better.
- The commander of Army B decides to order some of his troops to kill wounded enemies even with the battle raging. They get a -1 to their BR by they surely increase the casualties of the fallen.
- Army A is not so good. It composes actually of Undead. They are destroyed when they reach 0 hp. No casualties restored.
- The necromancers commanding Army A have devised a spell to re-animate fallen Obedient dead. Forget the previous rule. They restore 90% of their casualties and add in their numbers the casualties of Army B!

As I said, common sense is needed when you use a fast system to resolve a battle! I like my system, but please note the limitations of a mass combat system that I made in a few hours of work which were mainly spent on probability research and playtesting!

[alhoon]

Additions and Optional Rules:

- The DC should be actually 11+ target's BR, but I decided on 10 since it is easier to remember. Still that single point is making fairly much interest that I thought I should note it here.

- The system favors slightly small groups. I.e 2 groups of 500 1st level fighters work better against a group of 1000 1st level fighters. However 10 groups of 100 1st level fighters work much worse than a group of 1000 1st level fighters.
I believe this is realistic BTW.

- Optional: A unit composed by soldiers/troops that can gang up on enemies should get a +1 to BR. I.e If a unit of men goes against a group of ogres, the men (taking a single square) could more easily gang up on the ogres (which take a 10x10 square).
Also if a unit has greater numbers, its members could also gang up against enemies (except if the enemies are in a tight line). So I would suggest that if a group has twice or more members than the enemy group, they should take the +1 modifier for ganging up.

- Optional: If you use Heroes of Battle, don't Calculate your PCs in the EL of the group. Just monitor what they do and apply modifiers accordingly.

- Optional: Think well before you assign a CR to a hero/villain/soldier with a Character class. The DMG's assumption for Level=CR isn't completely right, since the classes are balanced in a way to make each one have a distinct role.
- A party of 4 7th level characters is about CR 11 in most cases.
- A 7th level rogue/ranger is a good warrior, but he is NOT CR 7 on a battlefield. Compare him with a hill giant, or any other CR 7 monster. NOTE: the 7th level rogue could not take a band of 20 trained soldiers by himself, but could kill an unsuspecting 7th level wizard!
- A martially trained 7th level rogue or a ranger in a battle that rages in light fog, with ample places to hide is CR 7 or even more.
- A wizard could be potentially very dangerous, killing hordes of enemies, but unless he is protected, he can be sliced down easily, especially if the enemy has a 7th level rogue around...
The above is good. Middle level characters (5-8 ) could be the decive force in a battle between a couple thousand soldiers. As numbers of lives involved go higher, so does the level requirement of the PCs.
Heroes of Battle or even the Great War Project could give you ideas about adventure hooks and things for the PCs to do in the heat of battle, that help turn the tide of battle.

- Optional: Generals! Their abilities should be able to influence the battle. So I suggest the following:
The leading generals should make an opposed Knowledge(War) or Tactics or even intelligence check. The leader with the higher total gives a +1 to the BR of his group, +1 for each 10 points of difference. I.e if the general of Army 1 rolls a 13 and the general of Army 2 rolls a 24 then Army 2 has a +2 to it's BR.

- Optional: Unit leaders. What benefit would a good plan provide if the subordinate officers fail to communicate it to their soldiers?
I suggest that each officer leading a Unit roll a diplomacy check (or leadership check, or intimidate check) with a DC 15 or the unit doesn't receive the bonus from the general's plan. The DC could be lower for units smaller than 100 troops and greater for a unit of more than 200 troops. Also the presence of an adequate number of lieutenants, sergeants etc could give a bonus to this roll.

[alhoon]

Some words of common sense:
- A 1st level warrior equipped with studded leather armor, small shield and a spear and with str 12 and con 12 is considered CR 1/2
A 1st level warrior equiped with a chain mail, a large shield and a sword, and with str 14, con 12 is still considered CR 1/2...
Take note of such things if you use the system and apply BR increases or decreases accordingly.

- An army of 250 1st level fighters, 40 3rd level fighters and 20 5th level fighters would obliterate a couple of hill giants... the system would probably not show any casualties.
Remember however that 1. It is impossible for all these 300 people to engage two hill giants at the same time. 2. That the hill giants will kill some low levels before they die with the rocks they throw and their clubs. Just not enough to drop the BR significantly.

[kottakinge]

Thanks Alhoon.
The system works

[alhoon]

You're welcome!
And it's "alhoon" not "Alhoon".