Mass Warfare Ad&D System
Recommendations:
Use figures or markers to indicate groups of units, 100s, thousands, or what ever makes sense based on the figures available and the number of units in the Army.
Discuss Strategy. Does the PC army intend to attack or defend? Are there defenses for one or both sides?
If some part of combat "Raises" dead Soldiers, I recommending adding these to "Remaining Forces" after the battle IF they would not be necessary to determine the outcome. This is usually applicable to overwhelming victories.
System:
1. Factor Attacking forces first. Roll a percentage dice to determine success. If 100 units are attacking a force of 100 on a level field with similar equipment, use the straight percentage.
EXAMPLE: Attacking Army is 59 percent effective. That means 59 soldiers killed the opponent they met.
2. Factor Defending forces second, but use their starting number. 100 defenders are 36% effective. They kill 36 of the 100 attackers.
3. Use 30 minute rounds for the battle scale. A Hill Giant, for instance may take out 50 men in 30 min of fighting easily if the field is packed enough.
4. If you can work on a scale chart do so. If not, the intent is to make a functional and fun system not an exact battle strategy system.
Modifiers:
Mounted Troops verses Standard Infantry = Roll with Advantage. Roll % twice and keep best result.
Mounted Troops Verses Pikemen Infantry with some planning for the attack by mounted troops = Pikemen Roll % with Advantage
Archers at disadvantage verses Mounted Troops. All Melee at advantage against Archers in melee range.
Archers get advantage if they are elevated more than 10 feet per 10 yards of distance from their target.
Melee can not counter attack against archers using ranged attack
Siege Equipment gets Advantage against Walls or other fortifications.
Infantry and Mounted Troops get advantage against Siege Weapons when in melee Range
Use common sense to give advantage or disadvantage in the effectiveness check.
When using individual PCs, you can judge if a % roll or a ThACO check makes more sense depending on their actions.