Topic: Crunchier AC Rules for Low Magic Campaigns

I am working out a variant armor class system intended to make a character’s choice of armor more meaningful. It adds some crunch, but a crunch that might be welcome in low or no magic campaigns where enchanted armor isn’t generally available.

I’m drawing some inspiration from a zine article that suggested dividing Hit Points into two pools, Meat and Grit. In that system, a character’s first hit die and constitution bonus is their Meat pool. All subsequent Hit Points are Grit. Grit represents an experienced character’s learned ability to protect their Meat. Grit absorbs hits before Meat, and heals faster than Meat. Losing grit represents a character becoming fatigued, accumulating nicks, or at worst breaking a finger. Things that won’t take away from the character ability to present an offense, but will cumulatively undermine the character’s ability to defend themselves. (A loss of 6 Grit might represent a twisted ankle when a character desperately dodges an axe that would have taken their head off if they stood still. The inability to dodge in that direction again is represented by only have 12 Hit Points to absorb the next hit instead of 18). Things that experience won’t protect you from, like falling off a cliff or poison, are applied directly to meat. You could also opt to apply successful backstabs directly to Meat points instead of applying a damage multiplier. If you want to give leveled characters a little bit more resilience against direct physical harm, you could let them continue to add their constitution bonus to the Meat pool as they leveled up.

I had think the article that coined the terms Grit Pool and Meat pool was in an issue of “Knock!” I’d like to cite it here, but can’t seem to find it.

Another rules variant I’m drawing from is  the optional critical hit rules from ACKS. Rather than get a critical hit on a natural 20, you score one when you beat your target roll by 10; and to the to hit die is exploding. Which means that if you roll a natural 20, you roll again and add the result to your first roll, and again and again if you keep throwing 20’s. (So you have pretty a good chance to roll a critical hit on a natural 20 if you needed less than 20 to hit in the first place).

So, I wanted a system where a character’s natural ability protects them from getting hit, and armor protects them from getting wounded when they do get hit. Rather than doing more points of damage when you score a critical, you apply the normal amount of damage directly to the Meat pool, which is just one die's worth of points. And rather than scoring a critical hit on a flat +10 above to hit target, the quality of your opponent's armor determines how much you have to beat the roll by to bypass the Grit pool. Plus, depending on a character’s Strength and Constitution bonuses, they can only wear so much armor before their Grit pool starts getting easier to hit. Here are the formulas I’ve been tinkering with. STR, CON, and DEX represent the ability modifier values of the respective attribute.

To hit Grit pool = 10 + Agility Bonus + Shield Bonus
Agility Bonus = Level + DEX –  Agility Penalty
Agility Penalty = [(Armor Bonus – (STR+CON)]/2, (cannot be less than zero)
Armor Bonus = Value of armor, per regular ascending  AC rules.
To hit Meat pool = 10 + Agility Bonus + Armor Bonus + Shield Bonus

One kink in this system is that first level characters receive no benefit from armor because they have no Grit pool. To address that, I expect to give the Meat pool it's own die, rather than take it from the regular hit die allotment. Classed characters will have their regular hit point allotment of one hit die per level, which is the grit pool in the system described above; and a single hit die of meat points. I’ll borrow a the page from LotFP that gives a character at least d6 hit die for their first level, but instead say everyone gets at least a d6 of meat points, unless they weigh less than 50lbs or something.

Loss of meat points represents wounds that won’t heal with a couple of days rest, but aren’t life threatening or debilitating until reduced to zero. At that point the wounded are out of the fight and you roll on the ACKS mortality table to find out how badly hurt they are when someone comes to their aid. The Mortality Table is a neat chart that tells you whether a character that was reduced to zero hit points is dead, maimed or just stunned; but not until someone takes a round to check on them. It factors in things like how many negative hit points they have, how long it took before someone comes to their aid, whether medical skill or magical healing is invoked by the first person to come to their aid. You can lose an eye, a leg, lose the ability to reproduce, or just die. It can mitigate character death, but can also incentivize characters to retire after suffering some permanent injuries.

Another kink is a lower base to hit (Grit) value, thus creating a greater overall hit point tax on the frontline fighters. To compensate for that I expect to change the rule requiring a 1 turn rest every 6 turns while exploring the dungeon, to granting CON worth of (Grit) hit points restored for every turn of rest. Characters without a CON bonus will have to rest for one turn for every point they are below +1 before starting to recover 1 point per turn.

An advantage is that mundane armor could be given interesting qualities, like a fancy brigandine giving the same protection as leather armor, but not causing an agility penalty. Or a suit of plate giving an armor bonus of 6, but only adding 4 to the agility penalty if the character pays a blacksmith a premium to have one custom made for them.

A thematic advantage is that less experienced or battle fatigued characters, (who have a lower ratio of grit points to meat points) will have less incentive to wear very heavy armor, and may even want to discard it in the case of fatigued characters. If a character doesn’t have enough Grit points left to keep the next hit from cutting into their Meat points anyway, there is no upside to incurring an Agility Penalty from their heavy armor armor. I find it thematically satisfying that an exhausted hero would discard some of their heavy armor, or that in inexperienced warrior might be more vulnerable trying to wear more armor than they can handle.

I’ve been having trouble getting players to the table for D&D lately, in part because of the pandemic, but also because of a move; so I’m throwing this out without any play testing other than rolling dice by myself. If anyone wants to play around with it in their game, I’d love to hear how the rubber meets the road with players. One easy tweak if it provides too big a disincentive to wear armor would be to change the agility penalty from [(Armor Bonus – (STR+CON)]/2 to (Armor Bonus)/2 – (STR+CON).

(Edited for syntax).

Last edited by Tarynt (2022-05-23 19:32:00)

Re: Crunchier AC Rules for Low Magic Campaigns

These see good.

Re: Crunchier AC Rules for Low Magic Campaigns


Reading back over my own post, I realize another kink in the system is that regular Hit Points (Grit) give no advantage to characters fighting without armor, because the regular to hit target number will be the same as the to hit meat target number. That would make an unarmored level 10 fighter just as vulnerable as an unarmored level 1 fighter.

I'll have to give this some more thought.

Last edited by Tarynt (2022-02-08 04:57:16)

Re: Crunchier AC Rules for Low Magic Campaigns

Perhaps I should have inserted a character's level as the base difference between the target to hit against regular hit points (Grit) and bypass their defenses (to hit Meat) instead of making it part of the Agility Bonus. Since an increasing hit point pool represents character getting better at defending themselves as they get more experienced, it fits thematically that a higher level should make it easier to tap into that pool to deflect killing blows.

This does mean that hits are going to get a lot more common, because the base to hit is going to be 10+/-DEX+Shield Bonus; without any other adjustment accept for a possible penalty for heavy armor. That will creating a higher hit point tax to exploration and encounters. But maybe that will be a good thing balanced against the proposed resting rules that make it easier to recover hit points during the adventure. I'll also go back to LotFP's base to hit target of 12 instead of 10 the next time I have a chance to playtest these house rules.

If this system works as intended, first level fighters will be discouraged from wearing armor that is heavy enough to cause an Agility Penalty because they only have enough regular hit points to take a hit or two before they start taking Meat damage regardless of armor. After a few levels and some more hit dice, they will want heavier armor to protect their flesh because they can afford to price hit point attrition into every fight. Then as their level starts to provide protection that rivals their heavy armor, they might choose to scale back down to lighter armor that doesn't cause an Agility Penalty so they will get less hits against regular hit points and have the stamina to fight longer without resting.

Re: Crunchier AC Rules for Low Magic Campaigns

This is where I am with this system now:

To Hit target = 12+DEX-(Encumbrance)
                       *Enc={[Armor Bonus–(STR+CON)]/2+any other penalty for being over encumbered} (but never less than zero)

To Penetrate target = (to Hit target)+(Hit Dice)+(Armor Bonus)+(Shield Bonus)

I'm calling the number you need to roll to hit the Meat Point Pool directly the "Penetrate" target, because the same optional ACKS rules that say a critical is scored by beating the to hit roll by 10+ does more interesting things than extra damage, like tripping an opponent; so I want to save the label "Critical" for that.

To Critically Hit target = (to Hit target)+10+(Hit Dice)

It might seam like a lot of admin to have three different target numbers. As previously stated, this system is intended replace some of the depth that would be lost in a game with little or no magic. The thematic benefit you get out of different values to Crit or Penetrate is that it will be easier to do one or the other to different targets depending on how heavily armored they are. Heavily armored and unarmored will feel different in an encounter because they have different vulnerabilities to lucky dice. The more heavily armored and encumbered an opponent is, the less likely you are to cause a sudden mortal would, but the more likely you are to knock them over or disarm them.

I'm borrowing from the LotFP 2E rules in the back of Eldritch Cock and have decided that meat point dice will be a function of Constitution instead of class. It will look like this:

Constitution     Meat Die
3,4                  d4
5-7                  d6
8-13                d8
14-16              d10
17, 18             d12

Like Hit Dice, you can reroll your Meat Die each time you level up; so characters will drift towards an optimal roll as they level up.

Last edited by Tarynt (2022-05-23 21:34:09)

Re: Crunchier AC Rules for Low Magic Campaigns

Hmm... Something about that doesn't look right.

+10 is too high a threshold  for a critical hit if we want over-armored characters to become vulnerable to a critical maneuvers before they become vulnerable to penetrating strikes. They would have to be wearing more than 10 points of armor, which isn't a thing if you aren't including enchantments.

So I could reduce that +10. Or, I could take the Enc penalty and either apply it to the Critical target instead of the base to Hit target; or apply it to both.

I need to sit down and roll some dice for a few hours to see what feels right.

Re: Crunchier AC Rules for Low Magic Campaigns

Seems like an awful lot of fiddling to achieve something for a low magic campaign you could probably just achieve more simply.

If you want to make lighter armours more attractive:

In medium armour any skill bonus' & Dex mods are capped at +1.
In heavy armour, no skill bonus' to physical tasks, no positive dex mods & rolls of 1 on checks for climbing, swimming etc are interpreted as disastrous.

If you still want the HP stuff.
Begin play with 6 Wounds + 1 class HD roll.
The initial 6 represents Wounds/Meat. And any dmg sustained to Wounds/Meat takes 1 week per pt to heal.

Any HP dmg sustained above the Wounds total just heal to full with a good nights rest.

Option B: for encouraging non armoured characters. The Naked Barbarian Rule: barbarians can use their Con/Str/CHa (pick whichever suits your mental map of barbarians) as their AC score. Stacks with a shield but not other armours.

Last edited by zarathustra (2022-05-30 12:45:45)

Re: Crunchier AC Rules for Low Magic Campaigns

I appreciate the feedback, but I'm not sure it accomplishes what I am going for.

I'm skeptical of systems where armor type caps the DEX bonus, because the benefit of heavier armor is always at least twice as good as the DEX bonus it curbs. That's why I wanted to implement something more like an encumbrance system. One where, depending on your combined STR and CON modifiers, wearing heavier armor will fatigue a character faster; represented by more hits against their hit points, but raise the target number to inflict damage directly to meat points. And the conceit that hit-points are something that you need to spend more of while wearing heavy armour, rather than a pool you are protecting with heavy armour, needs to go hand in hand with alternate rest rules rules that say you recover your CON worth of hit points for every 10 minutes of rest.

This is a system where regular hit points (grit) aren't your health. They are your stamina. They are the fuel your character is burning to use their armor effectively. And when you run out of grit your heavy armor becomes a liability that makes it easier to inflict wounds than if you weren't wearing it at all.

And I want this model to also allows armors to have two dimensions of quality. Let's say the baseline is that every +1 to AC adds +1 to armor encumbrance. Chainmail, for example, adds +4 to armor, but will also add 4 points to your encumbrance. A brigandine, on the other hand, is almost as expensive as chainmail even though it only offers +2 to armor class, because it only adds 1 point of encumbrance. And you can wear it casually. It is a more practical armor for someone that isn't marching towards a battle.

I've been having trouble working out a satisfying equation for finding the difference between the roll needed to drain grit points and the and the roll needed to drain meat points, but I think I have cracked it. My mistake was trying to make the roll needed to hit meat a modifier on the base roll to hit grit, when it's simpler and provides a better result when they aren't functions of each other. So:

To hit Grit=10+DEX-[armour encumbrance-(STR+CON)]

To hit Meat=12+DEX+HD+AC+Shield

The 10 and 12 might need to be dialed up or down, closer or farther apart with play testing. Right now an unarmored level 1 character would be 10 to hit grit and 14 to hit meat. A character with a Strength and Constitution of 13 each and wearing chainmail that provided 4 AC would be 8 to hit Grit and 18 to hit Meat. The same character at level 4 would be 8 to hit Grit and 21 to hit meat. (No DEX bonus in any of those examples).

Your suggestion for 6 wounds is kind of like what I'm already using, except that I'm having my players roll for wound points when they get wounded using the Constitution derived hit dice in the LotFP playtest notes from Eldritch Cock.

On the upside, I have finally scraped together a regular group so I'll be able to start putting my ideas to playtest.

One thing I haven't come up with yet is a good rule for diminishing returns for multiple rest stops during an in game day.

Last edited by Tarynt (2022-08-03 23:40:11)

Re: Crunchier AC Rules for Low Magic Campaigns

The first session went well. The party was exploring Dwimmermount with four 1st level characters. It wasn't the first foray into this dungeon, but it is early in the campaign. My house rules felt pretty seamless, but the party was being very careful and tried not to get into any fights where they didn't have the element of surprise, so I haven't executed enough combat to speak confidently on it yet.

I encountered two situations the house rules didn't speak to yet. One was poisonous bites, which they encountered twice. Giant Centipedes and Crab Spiders. I reasoned that a bite had to penetrate armor to inject the poison, so a roll to hit Meat is required. (I could have said that at least 1 meat point of damage is needed, but Giant Centipedes don't do any points of damage. They just cause a saving throw against poison with a successful attack). This meant that armor mitigates a lot of the save or die risk  of fighting poisonous monsters compared to the regular rules. So far that is good thing. The session would have been over within 20 minutes of game time into the expedition (less than five minutes of real time) with the whole party sickened by centipede bites if we were playing with regular rules. And possibly 3 out of 4 characters dropping dead on the walk back to town from the delayed effect of Crab Spider bites.

They also encountered a Wight. An unlikely reaction roll meant the Wight wasn't actually hostile during the encounter, but it did prompt some thought and discussion of which attack roll would a Wight's energy drain attack use. We decided that because we imagine it as an aura of unnatural cold that sucks warmth out of a body, that would go right through armor if a Wight grabbed you. In hindsight, I think I would make an exception to Fur or Hide armor, or anything that would reasonably be designed to protect from cold. (But also assume that any of that would be too warm to wear if you weren't actually in a wintery environment.

Last edited by Tarynt (2022-08-08 22:55:46)

Re: Crunchier AC Rules for Low Magic Campaigns

Another rule I that I think I need to rethink after play is how meat points are rolled. Both fighters ran out of Grit HP towards the end of the expedition, and both rolled a 3 when I asked them to roll up their Meet Points (one with a d8, and the other on a d10 because of her higher Constitution). They were both lucky that the damage overflow was less than 3. The thief suffered a penetrating blow, but fortunately rolled 8 Meat Points against 4 points of damage.

The rationale behind rolling up a new pool of Meat Points every time a fully healed character takes new meat damage was to enhance suspense by keeping every attack dangerous. An attack with a dagger could kill you if it penetrates and you roll low with your Meat Die. It also meant the a low roll wasn't a long term weakness, because you would be re-rolling the next time you got hurt. But seeing that 3 out of 4 characters only made it out alive because they made lucky rolls, as opposed to maybe 1 out of 4 not making it because of an unlucky roll, has left me with the feeling that that is too much deadly danger that won't be mitigated by leveling up.

What I'm going to do instead is a variation of how I handle Regular (Grit) HP. I make characters re-roll all of their Hit Dice when they level up. If it's higher than your current total, take the new roll. If it's lower, gain 1 HP. I'm going let characters re-roll their Meat HD every level. If they roll under the current total, add 1 Meat Point to their pool. This means some characters are going to roll close to their max early and start building above the max that they can roll from an early level, while other's might not start doing that until level level 6 or 7 if they are very unlucky.

This isn't going to help these characters that rolled low now, while they are still level 1, but it will decrease the likelihood that they are killed off by bad rolls after the players have invested significant time into them.

Last edited by Tarynt (2022-08-10 20:03:13)