While waiting for D@W, I began looking for other rules that could be used easily with ACKS. These rules are converted from the skirmish rules originally created for the Birthright setting.
The base unit for this system is a 20-creature unit.
Unit stats: Units of 10 halve their hit points and damage inflicted.
Unit hit points: a unit has 1 hit point per hit die. For example, a unit of 20 infantry (0-level humans) would have 20 hit points. A unit of light cavalry (0-level humans and light horses) would have 60 hit points. A unit of ogres would have 80 hit points.
Unit damage: A unit’s base damage is equal to 20 minus its attack throw. 0-level humans have a base of 10 damage. Ogres have a base of 14 damage.
Combat: A unit’s damage dealt in combat is equal to its base minus the opposing unit’s armor class. If the creature has multiple attacks that each inflict at least 6 damage, double the damage inflicted. If the creature’s maximum damage from an attack is 12 or higher, double the damage inflicted. If the creature has multiple attacks that can cause 12 or more damage, triple the damage inflicted. These modifiers are not cumulative.
Example: A unit of 20 ogres with two-handed swords is attacking a unit of 20 skeletons. The ogres have a base damage of 14. This is reduced to 12 by the skeletons’ AC of 2, then doubled to 24 because the ogres have a single attack inflicting 1d10+3 damage (maximum 13). The ogres will destroy the 20 HD of skeletons in a single round. The skeletons have a base damage of 10, reduced to 6 by the ogres’ AC of 4, unmodified because they have only 1 attack dealing 1d6 damage.
Units combating each other also roll an opposed die of a size equal to their primary weapon damage; the unit with the higher roll adds the difference between the rolls to the damage it inflicts. A unit commanded by a name PC or NPC gets +1 to its damage. A PC or NPC with Military Strategy adds an additional +1 for each level of Military Strategy, up to +3. Magic used in combat adds +1 per 2 levels of the spell cast. Surprise or ambush will add +2 for the first round of combat.
Once a unit loses half its hit dice, it inflicts half damage and rolls the next smaller die size. Once reduced to one-quarter hit dice, the die roll is reduced by two sizes (total).
Example: The skeletons get lucky, and roll a 6 on 1d6 compared to the ogres’ 4 on 1d10. This means they inflict an extra 2 damage. The skeletons are still destroyed, but they inflict a total of 8 damage in the one round they fight.
Casualties after a combat are 50% deaths, 50% injuries for living units. Undead unit casualties are 100% destroyed, but 50% can be reanimated if there is someone to cast animate dead on the remains.
Example: After the combat, the ogres have suffered 8 HD of casualties. Since ogres have 4 HD each, there is one dead ogre and one incapacitated ogre who will recover if given time. All of the skeletons have been destroyed, but an arcane character who can cast animate dead could reanimate 10 of them.
Hopefully this will give people a way to play small-scale battles more easily than rolling every die for every character, particularly for name-level characters with their followers.
The original rules don’t cover ranged troops, but they can be handled by using encounter ranges, combat movement, and allowing ranged troops to attack at range without being counter-attacked. Note that in the case of an unopposed attack, the dice should still be rolled, but have no effect if the melee-only unit rolls higher than the ranged unit.