Crunchier Armor Class Rules

I came up with this system to make a character’s choice of armor more interesting. If you use it, characters may want to change what kind of armor they wear depending on what kind of fight they are expecting, and will want to change things up as they level up and become more competent at defending themselves. It’s a bit fiddley compared to the basic rules. I’m using it in a campaign where the players don’t have much access to magic, so this is replacing some other fiddley bits I took out.

All humanoid characters have two pools of Hit Points, the subtypes are Grit Points and Meat Points. You get 1 Hit Die of Meat Points for being a level 0 humanoid, and Grit Points progress as regular Hit Points do with class level. When a character levels up, they reroll all of their class dice and take the new total, or add 1 to the old total, whichever is greater. They also reroll their single Meat Die, and take either the new result or the old total+1, whichever is greater. (This will eventually allow characters to accumulate more meat points than they can roll as they level up).

Armor class is also subdivided into two values, Evasion Class and Armor Class. Evasion Class is the lower of the two values, and hits that successfully overcome it will cause damage against Grit Points. Grit represents one’s stamina and skill at actively defending oneself against attacks that weren’t avoided entirely. Lost Grit points at worst represent a twisted ankle or a broken finger. The numerical difference between Evasion Class and Armor Class is the range in which a character is able to actively defend themselves by blocking with their weapon, armor or shield. The loss of Grit Points to hits within this range represent the spending of one’s stamina to actively block potentially deadly blows. Hit rolls that beat a character’s Armor Class penetrate their defenses and apply damage directly to their Meat Points.

Evasion Class is DEX-(Armor Encumbrance)-(Other Encumbrance)*. Evasion class will often be negative. By design, this system is going to levy a greater Hit Point tax against front line fighters during almost every combat encounter. This is balanced by alternate rest rules that will be described below.

The default value for Armor Encumbrance is the (Armor Bonus)-(STR+CON), but can’t be lower than zero. Also, this opens up a second dimension of quality to armor; armor that inflicts less of an Armor Encumbrance penalty proportionally to the Armor Bonus it offers. For example, chainmail has an Armor Bonus and Armor Encumbrance of 4, while a similarly priced brigandine might offer an Armor Bonus of 2 but only have an Armor Encumbrance of 1. Finely made or custom fitted armor might also have less Armor Encumbrance.

*(Other Encumbrance is optional and just refers to whatever other encumbrance rules you are using).

Armor Class is 2+HD+DEX+(Armor Bonus)+(Shield Bonus). This value represents the character’s ability to actively defend against attacks that would have otherwise hit, and by beating it the attacker bypassed the character’s defense and drew blood. Bypass Grit Points and apply damage directly to meat points. When Meat points reach 0, go down for the fight and consult the MORTAL WOUNDS table, regardless of how many Grit Points you have left.

If a level 1 character attacked another level 1 character with chainmail, a shield and no STR, CON or DEX bonuses; they would need to roll an 6 to inflict damage against Grit Points and a 19 to bypass Grit and Damage Meat Points. If that same target had a +1 to STR, CON and DEX; they would need to roll a 9 to hit Grit and a 20 to hit Meat.

Disregard the regular rule that requires a party to rest for 1 turn every hour. The party can rest whenever they want to recover Grit. Characters will recover 1+CON Grit Points for every turn they rest. Characters with a negative CON will have to rest for a number of turns equal to the penalty before they start recovering 1 Grit/Turn. Don’t forget to roll for extra random encounters during multi-turn rests. During the rest, Characters roll their Grit Hit Dice. If the total is lower than their current Max Grit HP total, that is the new Max for the rest of the day. If the roll is greater than their current Max Grit HP, lower the Max by one for the rest of the day. Minimum new Max HP is Current HP+CON. (Note that characters with a CON penalty might feel worse after resting in a musty old dungeon).

Use common sense to decide how special attacks are resolved. While playtesting these rules, my players encountered Crab Spiders. I decided a spider attack needed to damage Meat Points to inject poison. They also encountered Giant Centipedes, which have a poisonous attack but cause no damage; so I decided they needed to penetrate the character’s Armor Class to do anything. This means that Armor is much more effective against poisonous monsters than in the default rules.

They also encountered a Wight. We discussed it and decided that a Wight’s energy drain attack takes the form of an unnatural cold that sucks the warmth from a living body. As we all visualized it, that cold would easily conduct through metal armor if a Wight grabbed you. That means that heavy armor makes you more vulnerable to energy draining undead if you don’t have the STR and CON bonuses to offset the Armor Encumbrance. (In hindsight, I think a would have added the armor bonus to the saving throw, to represent the extra seconds you would have to break free before the cold reached your flesh through the armor, but they managed to avoid that fight so I didn’t have to think it that far through during play).

This system, so far, seems totally compatible with the Critical Hit rules from the ACKS Heroic Fantasy Handbook. (Avoiding confusion while using the two systems together is the reason I divided AC into EC and AC, instead of just calling the higher value a Critical Hit). In fact, the assumption that you’re using the exploding to hit die from the Critical Hit rules is baked into my system. If you use them together and use the Evasion Class value as the number you need to beat by 10 to pull off a critical, you will find that heavily armored opponents are more vulnerable to the trips, disarms and stuns and such of Critical Hits than they are to wounds; and lightly armored opponents are going to be less vulnerable to Critical Hits than they are to being wounded by a high roll. That seemed to be thematically appropriate to me and was an effect I was deliberately going for.