Mass Combat

Basic Mechanics:

1. Each side selects a Force Commander.
2. Each Force Commander rolls a d20 (called a Combat Roll) and modifies the results using the charts below.
3. Then proceed to the "Battle Results and Casualties" section for the outcomes.

Modifiers

All modifiers are calculated using the average for the army. Use as many or as few modifiers as desired in order to make combat as simple or as involved as you desire; make sure you consider the same modifiers for both sides. This combat system assumes that at the very least each army possesses infantry and archers or missile throwers of some sort, making up 10% of each side. If either are missing then apply a -2 penalty to the deficient army's combat roll.

Base Movement Modifier
5ft. or less -3
10ft. -2
20ft. -1
30ft. +0
40ft. +1
50ft. or more +2
Defense Modifier
1 or less -2
2 +0
3 +1
4 +2
5 +3
6 or more +4
Base Attack Bonus Modifier
0 -2
+1 to +3 +1
+4 to +7 +2
+8 and up +3
Troop Ratio Modifier
1:1 +0
2:1 +2
3:1 +4
4:1 +6
5:1 +8
6:1 +10
7:1 +12
8:1 +14
More than 8:1 +16
Discipline Modifier
Untrained -2
Trained +0
Disciplined +1
Highly Disciplined +2
Experience Modifier
Young -2
Experienced +0
Veterans +1
Crack Soldiers +2
Equipment Modifier
Poor -2
Average +0
Masterwork +1
Charisma Score of the Force Commander Modifier
3-9 -2
10-11 +0
12-13 +1
14-15 +2
16-17 +3
18 and up +4
Cavalry Modifier
None -2
10% of the Force +0
20% of the Force +1
100% of the Force +3
Half of the Cavalry are archers +1
Miscellaneous Situations Modifier
Force Commander’s Knowledge (Military) skill result varies
Missile troops outrange opponent’s missile troops +1
Advantageous Terrain +2
Defending Stronghold +5
Defender Entrenched +1
2 or more Siege Engines vs. Stronghold +3
Extreme Weather Conditions -3
Force Dehydrated -3
Force Malnourished -1
Disadvantageous situation (lighting, weather, etc.) -2
Every three defeats in one year -1
Every 5 victories in one year +1
New Force Commander -2 for each one per year

Fatigue

For every four weeks on the move (not a forced march) and engaging in any combat without at least two full days rest, troops must make a FORT save DC 15 using the saving throw of the average level soldier, but modified by the leader's charisma bonus or suffer -1 penalty to their total combat roll modifier cumulative monthly until at least two full days rest have been taken for each missed month.
After a forced march for a period of one to two days, the army must make a DC 15 FORT save using the saving throw of the average level soldier, but modified by the leader's charisma bonus or suffer a -1 to all combat rolls within the next two days. If the army wishes to continue forced marching, the DC of the Fort save increases by two for every 1-2 day period in which they march. Armies can continue marching after they fail a Fort save, but penalties to combat rolls are cumulative, and they are not recovered until the army has rested for as long as it has forced march. In any case an army can fail no more than five checks and continue forced marching until it must rest.
After combat, for every loss an army suffers it must make a DC 15 Fortitude save, modified as above or suffer a -1 on all combat rolls. The DC of this check increases by 5 for every subsequent loss that the army suffers without having at least a two-day rest in between losses. The penalty to the roll increases by one for every failed check up to a maximum of 5 to roll. The victor must also make a fatigue check after combat (DC 15 modified as above), but they gain a +2 morale bonus to their save. The endurance feat, possessed by at least 75% of troops, offers a bonus to save according to the rules outlined for the endurance feat.
Each combat roll represents six to eight hours of combat. Troops who wish to continue combat for an addition six to eight hour period straight suffer -2 fatigue penalty to combat rolls unless reinforced with additional troops representing no less than 50% of force. This modifier becomes -4 unless a fortitude save at DC 15 is made as expressed above. The endurance feat, possessed by at least 75% of troops, offers a bonus to save according to the rules outlined for the endurance feat. All percentage casualties lost are lost from the remaining percentage of troops.
The army with the over-all highest roll is the victor. Then use the procedure below to determine the results of the battle.

Battle Results and Casualties

After each Side calculates its total modifier using the above list of modifiers, each Side generates a random number between 1 and 20, and the army with the over-all highest roll is the victor. Then use the procedure below to determine the results of the battle. All casualty losses are 60 % wounded, 10% captured, and 30% killed. The DM should roleplay any possibility of PC capture or death.
In the event of a tie, both sides simultaneously disengage to regroup. Both sides suffer 10% casualties with no ground lost.
Every roll represents a 6-8 hour period of combat, although there will certainly be periods during this time when combat slows or stops and then restarts.
All percentage casualties lost are lost from the remaining percentage of troops.
Loser rolls a d20 to determine losses.

Failed Roll By Results
1-2 10% casualties; no ground lost
3-4 15% casualties; 50% retreats 1 hex
5-6 20% casualties retreats 1 hex
7-8 25% casualties, retreats 1 hex
9-10 30% casualties, 50% 50% chance of commander lost or killed or important info or equipment taken by victor (if NPC), retreats 1 hex
11-12 45% casualties; 60% chance of commander lost or killed (if NPC) or important info or equipment taken by victor; retreats 1 hex
13-14 50% casualties; 90% chance of commander lost or killed (if NPC) or important info or equipment taken by victor; Army is scattered unless the Force Commander makes a Will save (DC 12). If the Force Commander is captured or killed, a new one is appointed to make the roll. If save is successful, troops are pushed into stronghold (if defending one) retreat 1 hex.
15-16 65% casualties; army routed unless the Force Commander makes a Will save (DC 15). If the Force Commander is captured or killed, a new one is appointed to make the roll. 90% chance of Force Commander lost or killed (if NPC) or important info or equipment taken by victor. 50% chance that a majority of survivors can be captured or hunted down.
17-23 75% casualties; army routed. Remaining commanders captured or killed (if NPCs)*. Surviving 25% of army escape unless somehow trapped.
24-27 85% casualties; army routed. Remaining commanders captured or killed (if NPCs)*. Surviving 25% of army escape unless somehow trapped.
28-30 90% casualties; army routed. Remaining commanders captured or killed (if NPCs)*. Surviving 25% of army escape unless somehow trapped.
More than 30 Victor has totally destroyed his opponent; there are few survivors

Victor rolls a d20 again to determine his own losses
//If the victor has won by +5 to +9, he gets a +1 on his casualties roll, +10 to+14, he gets a +2, +15 to +19, he gets a +3, +20 to +24, he gets a +4, and +25 or more he gets a +5 on his casualties roll. //

d20 Roll Result
less than 1 Roll again with -5 penalty. If the result from the penalty is again 1 or below, the victor suffers 100 % of loser's casualty percentage; 50% chance a commander as been lost(if NPC). If this result is attained a third time, the victor loses 110 % of the loser's percentage, and there is a 75% chance a commander has been lost.
1 90% of loser's casualties, 25% chance a commander has been lost.
2-5 20% - 80% (2d4 x 10) of loser's casualty percentage; 15% chance a commander has been lost (NPC only)
6-11 10% to 60% (1d6 x 10) of loser's casualty percentage; 10% chance a commander has been lost (NPC only)
12-15 10%-30% (1d3 x 10) of loser’s casualty percentage
16-19 5% to 20% (1d4 x 5) of loser's casualty percentage.
20 5% of loser's casualty percentage.
More than 20 Roll again with +5 bonus. If this result is attained again, the victor suffers no casualties and receives a +1 modifier to next combat roll within three days.
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