Mass Combat

These are my rules for mass combat, inspired by this post and based on the Warhammer rules. These are tailored for my bastard 3.5, but could easily be applied to most D&D or RP rules.

Use one model to represent a unit or group of men. Assume they all have the same stats and stuff, if they don't use only what the majority of the unit has. One inch, square or hex should represent either 30ft or 60ft so either a single move action, or a double move action covers it. Infantry units are generally 100 men and Cavalry generally 40 men.

Anything one could do in normal tactical combat, can still be done with the follow changes;

Movement as normal except it is a half move to change facing of a unit and a full move to about turn.

When in melee, both sides attack in each turn to simulate the press of the melee. Both sides roll to hit, but they will automatically do damage in 'amount of soldiers' as theit weapon damage rather than HP, as in the bloody melee, even the strongest warriors are pressed in and dragged to the ground etc.

If a unit's attack rolls beats the enemy AC, then that amount of extra casualties is done. Critical hits still apply, and represent a very strong enemy surge or good morale or some such. Any bonuses for charging (including lances) still apply.

So in a combat turn two units will roll off with their attack rolls against each others ac and deal their weapon damage in casualties, with an extra casualty caused for every point they beat the enemy ac by (in my system these casualties are reduced by DR from armour as well). All normal bonuses for flanking and charging etc still apply and units fight as if at full strength regardless of casualties taken.

Ranged units use the same rules, except they receive no opposed attacks obviously. So they automatically do their ranged damage, and an extra casualty for every point they beat the enemy AC by.

Morale checks are taken when a unit reaches 75% of its original strength of numbers. The check is DC10. A subsequent check is taken when they are dropped below 50% @ DC 15 and subsequently every time a unit is damaged thereafter. These are versus the highest command skill (or charisma) in the unit (so generals will probably assign officers with names and stats to most units, who if they have no ranks in a command skill equivalent have a high intimidate or charisma).

These checks are modified by the difference, positive or negative, between each units kills in that turn. So if a unit reaches 75% but did 2 more kills than the enemy unit that turn, then the check is DC8 not 10. If the opposing unit also dropped beneath 75% that turn they would check at DC12 not 10.

If a unit fails the command check it breaks, it immediately makes a move action away from the winning unit provoking an attack of opportunity as normal. Make a opposed dexterity checks to simulate the other unit trying pursue, (cavalry should automatically catch infantry or receive massive bonuses to this check). If a unit doesn't wish to pursue they must make a command check DC 10 to refrain. If a unit is 'caught' then then the chasing unit gets to move with the fleeing unit, staying in combat and make an additional attack, with no opposing attack roll. In subsequent turns make the same dexterity check until either the fleeing unit manages to escape or the pursuers refrain from following.

Once a unit is broken and escaped combat they may make a rally checks to stop fleeing, otherwise they continue to move full speed away from the fight, probably to cover. You may make a rally check in each of your turns, and it is a command check as per the DC of the break checks, so DC10 for a unit below 75% and DC 15 if the unit is below 50%. In addition this check should take an additional -1 for each 5 casualties below 50%. strength.

After battle D% of casualties of each unit are actual deaths, permanent injures and perhaps a further D% of these actual casualties are prisoners of war. These are both rounded down and any casualties not in this group were only minorly injured or knocked unconscious and can still fight in a subsequent battle.

Characters in combat take d4 attacks per round and these roll to hit as normal, and the character takes normal HP damage. When the character attacks, keep a tally of the damage they do, whenever they have dealt enough accumulative damage to normally kill one of those creatures in the unit, they count as having done a single casualty (this is the same for ranged attacks from characters, who can probably get and additional +4 to hit because of circumstances). If a character is stupid enough to charge a unit by themselves, they should take 9-10 attacks per turn from being attacked by multiple soldiers or creatures at once.

The way I am thinking of adjudicating mass magic killing is just figuring out how many troops in the unit would normally be effected, given they are standing ranked up all next to each other (each in a 5ft square next to each other) by the area of the spell and the the caster can just roll damage against them as normal, doing casualties if they successfully kill single soldiers and keeping track of damage done against others, assuming that if they hit the unit with another spell they will target those same soldiers first, but this accumulative damage only applying to that spell caster. Currently I can't think of a better way to model this that isn't ridiculously overpowered or under powered for casters.