Quick Combat: Redshirts and the Save Versus Death

When there are large quantities of combatants, especially of the same type, there's no reason to roll individual attacks and damage, and no reason to keep strict, detailed records of who's dying and who's left. Of course there's nothing wrong with fighting them normally by making a d20 roll and then rolling damage, but why do that for every combatant when there's a bunch of them? Assuming that they're facing opponents of roughly equal strength, it can be streamlined into a single roll with a little math. Redshirts with low HP, AB and damage are easy to model, so we can just make a roll for each individual or unit without tracking their HP if we calculate the chance of them dying from an attack. Thus, they get two states: "Dead" and "Not Dead" (or "Not Dead Yet"). If they fail a save, they are Dead. If they succeed, they are either Not Dead (fully alive) or Not Dead Yet (reduced strength, suffer a Morale check, or other negative effect or complication.

Combatants are categorized into a few types to account for different HP and AC values: 0HD "Grunts" with no armor, 1HD "Troops" with Leather armor, 1HD "Elites" and Level 1 Fighter "Super Elites" with Chain. As shown below, this scales nicely with the d6 system, with each category having a 1 point increase and being easy to keep track of.

0 HD Grunts/Non-Combatant Retainers (all but Guards, Guides, Mercenaries, Sailors)
1 HP. Will die if hit, regardless of weapon damage.
45% chance of being hit (12 AC). Round up to 50% because they're mooks and have no idea what they're doing when they're in combat.
50% chance of being hit, upon which they will die, equates to a 3 in 6 save versus Death.

1 HD Troops/Combatant Retainers (Guards, Guides, Mercenaries, Sailors)
2 HP. 83% chance of death from d6 rolls if they're hit.
35% chance of being hit (14 AC)
30% chance of being hit and then dying. Round up to 33% because war is hell, which equates to a 4 in 6 save versus Death

1 HD Elites
4 HP. 50% chance of death from d6 rolls if they're hit.
25% chance of being hit (16 AC)
12.5% chance of being hit and dying. Round up to 17% chance because even the best are at the mercy of luck, which equates to a 5 in 6 save versus Death.

Level 1 Fighter Super Elites
 8 HP (minimum HP according to character creation). Assuming d6 damage rolls, they will take at least 2 hits to kill.
25% chance of being hit (16 AC). The probability of them dying in 2 rounds is 40% (8 or more damage from 2d6, even though the 2d6 is spread out over 2 turns). They have an 83.75% chance when 3d6 is rolled.

They're tough bastards. 5 in 6 save and require 2 fails for them to die. If they're led by someone special, 3 fails.

Henchmen should have their own stats.

Success: Survival. They continue on at full strength.
Failure: On a failed roll, they're dead. In the case of a unit, casualties are suffered.

Optional:  

Casualties: When using large units, a success lowers the Save by 1 going forward, reducing their strength and fighting ability. When the Save reaches zero, the unit dies.  

Critical Success: On a roll equal to the Save skill, troops survive and kick some ass and get a bonus, such as a penalty to the opposing side's save, a morale bonus, bonus to the next roll, etc.

Human Shield: Damage to a PC can be redirected to their Henchmen instead. May trigger a Loyalty or Morale check, at Ref's discretion. 

Morale Check: On a roll of 1, the character lives, but feels like they brushed close with death and contemplates retreat. Roll another d6, using the unit's Save as their Morale.

 

The d6 damage assumption gives strong compatibility with B/X RAW and OSE options, and the overall hit/kill probabilities are almost entirely in line with Chainmail. These calculations assume they are attacked by characters with no Attack Bonus wielding weapons doing d6 damage. Saves could be modified with penalties if they are being attacked by PCs with significantly higher AB or higher HD monsters, remembering that for every +3 AB there is an additional 1 in 6 chance of hitting. For most LotFP PCs, this will barely change things as they only get a +1 AB which does not improve.