"Hits" instead of "Hit Points"
Faster combat? maybe. Old-school? Definitely.
So, been thinking about this hack a lot lately, after looking at how the original Chainmail (and various other wargames) manage combat damage:
There are no “hit points”.
Instead, monsters can withstand a number of “hits” equal to their level / “hit dice”.
PCs and NPCs start with a number of “hits” at level one based on their Constitution:
5 or less: Two hits
6 to 15: Three hits
16+: Four hits
Fighters and dwarves gain +1 hit at levels 1, 3, 5, 7, and 9.
Other classes gain +1 hit at levels 3, 6, and 9.
Weapon damage is still based on dice rolled after a d20 attack throw, but:
Attack throw thresholds are not based on armor; instead they are purely based on the strength and level of the attacker.
THAC0 is the threshold to achieve a critical hit if the damage roll penetrates the target’s armor, or the threshold to inflict a single ‘hit’ if the damage roll doesn’t penetrate the target’s armor.
Half THAC0 (round up) is the threshold to “land a blow”, which then rolls the weapon’s damage to check if the hit penetrates the target’s armor.
The target’s Dexterity and whether they’re using a shield will affect THAC0 as normal.
Weapons get a number of d6 “damage dice” based on their size:
light weapons get one damage die (dagger, shortsword, club)
medium weapons get two damage dice (longsword, mace, spear)
heavy weapons get three damage dice (greatsword, battleax)
spells and other damaging effects use d6 damage dice
Armor determines the “penetration threshold” for each damage die:
vs. an unarmored target, each die inflicts a hit on 2+
vs. light armor, each die inflicts a hit on 3+ (leather)
vs. medium armor, each die inflicts a hit on 4+ (chainmail, half-plate)
vs. heavy armor, each die inflicts a hit on 5+ (full plate)
vs. dragonscale or similar structures, each die inflicts a hit on 6+
Masterwork armor increases the threshold by 1, and “piercing” weapons reduce the effective threshold by 1, but the threshold can never be higher than 6+ or lower than 2+.
spell and other elemental damage inflicts a hit on 4+, and inflicts a special condition on a ‘6’ (like being lit on fire or stunned)
A “critical hit” still happens whenever the attack throw rolls a ‘20’, or when a thief hits with a backstab. When a critical hit happens, the target has to save vs. death after the attack damage is applied; if they succeed, their current remaining ‘hits’ are halved. If they fail, their remaining ‘hits’ drop to zero and they have to start rolling to stabilize.
At zero ‘hits’, a creature is dying.
They have to save vs. death at the end of each combat round; if they fail before they are healed, they die.
If they succeed, they can roll a d6 to stabilize, with a threshold based on their Constitution:
Con 5 or less: 6+
Con 6-8: 5+
Con 9-12: 4+
Con 13-15: 3+
Con 16+: 2+
Healing is likewise rescaled:
Cure Light Wounds and similar-scaled effects heal one hit.
Cure Serious Wounds and similar-scaled effects roll a d6; if the result is greater than the creature’s current hits, it heals up to that many hits. Then, it heals one additional hit.
Resting heals one hit per N days, where N depends on the resting creature’s maximum total hits:
2 max hits: 1 hit per 4d6 days of rest
3 max hits: 1 hit per 3d6 days of rest
4-6 max hits: 1 hit per 2d6 days of rest
7+ max hits: 1 hit per 1d6 days of rest