Combat Realism - Defense and Armor Options (5e Variant Rule)

Combat Realism - Defense and Armor Options

Combat in Dungeons and Dragons 5th edition is a well-balanced but somewhat abstract system where success is determined by an attack roll versus an armor class (AC), followed by a damage roll that reduces the target's hit points (HPs). There are two common criticisms of the 5e combat system:

Defense: A higher level character gets better at hitting targets but not at avoiding being hit (only reflected in abstraction by increased HPs)

Damage reduction: Armor does not directly reduce damage (reflected in abstraction by reducing the chance of being hit)

Both of these can affect the sense of realism: players expect the 6 second combat round to represent a single attack sequence, with the attacker's skill pitted against the defender's, and with armor able to either deflect or cushion a blow. Variant rules (official and home-brewed) have been developed to improve that realism and there are learnings from other role-play combat systems. Indeed, D&D v3.5 included official optional rules for Armor as Damage Reduction (see elsewhere on this site, including an excellent port into the 5e system) and an optional Defense Bonus (also here on dandwiki) that could substitute for Armor (but not stack). Various official Combat Options supplements in other versions of D&D aimed to address other aspects. While none of these are directly described in this article, it has certainly benefited from a diverse range of such influences. The options proposed below are intended to be a near-definitive set of optional rule modifications, each of which represents an alternative way to improve combat realism by considering the defender's skill and the ability of armor to reduce damage. The rules have been optimized for melee combat but can apply equally well to ranged combat and spell attacks. Enough detail is presented to clearly describe the core mechanics and apply them in your own games but finer details would bog it down and are best left for a future wiki.

Option 0: If It Ain't Broke

The current system works. It is not satisfying as a blow-by-blow description of realistic combat but it has been extensively play-tested and is balanced. HPs do mean that higher level fighters can absorb more attacks. Armor does reduce the total amount of damage taken. Feats, Fighting Styles and Battle Master options give martial classes advantages in combat. Multiple attacks reflect the ability for more skilled fighters to make more shots count in their 6 seconds. Complex circumstances are neatly represented by the advantage/disadvantage system. No-one will blame you if you stick with the tried and tested.

Attack bonus: Unchanged

Defense: Unchanged (AC)

Damage: Unchanged (consider not allowing Dexterity or Charisma to substitute for Strength)

Damage Reduction: Unchanged (none)

Impact for Monster Stats: None

Option 1: Add Defense (only)

The smallest change is simply to use the core rules and add a defense factor. This does not address the issue of damage reduction from armor but is a simple first step. Using proficiency keeps with the 5e aesthetic and is simpler than the v3.5 official option. It can also stack with armor if we add a fixed -4 compensation factor (to balance the +2 to +6 proficiency bonus), as opposed to the v3.5 official option which could not stack. Note that proficiency, as with all options below, only applies if the defender is using a weapon or shield that they are proficient with (unless unarmed and proficient in unarmed combat) and if they are proficient in any armor they are wearing.

Attack bonus: Unchanged

Defense: AC + proficiency - 4 (i.e. just add proficiency bonus but compensate with a fixed -4)

Damage: Unchanged

Damage Reduction: Unchanged (none)

Impact for Creature Stats: Easy adjustment

- Attack bonus: Unchanged

- Defense: AC + (Attack Bonus - STR)* - 4 (a quick alternative is just AC -2 for low level creatures, to +2 for high level creatures)

- Damage Reduction: Unchanged (none)

(* Attack Bonus - STR approximates Proficiency Bonus. Or simply derive from Challenge Rating using p274 of the DMG, which is basically the same as treating Challenge Rating as Character Level: Challenge <4 = Proficiency Bonus 2, Challenge 4-7 = Proficiency Bonus 3, etc)

Option 2: Add Damage Reduction (only)

This is based on the v3.5 official option and is well-described elsewhere on this site. Note that Armor contributes fully to Defense and half to Damage Reduction, overall increasing its contribution.

Attack bonus: Unchanged

Defense: Unchanged (AC)

Damage: Unchanged

Damage Reduction: Damage reduced by ½ (Armor AC - 10) (note: shield, DEX, etc do not contribute)

Impact for Creature Stats: Some adjustment

- Attack bonus: Unchanged

- Defense: Unchanged

- Damage Reduction: ½ (Armor AC - 10) (note: remove DEX, shield bonus, etc from AC first)

Option 3: Mixed ("v3.5+")

Essentially combine Option 1 with Option 2. An addition here is to reduce Armor's contribution to Defense by the amount it contributes to Damage Reduction, so that its overall benefit remains balanced. Effectively, half the armor benefit goes to Defense and half to Damage Reduction. A further advantage of this is that the -4 adjustment is no longer needed.

Attack bonus: Unchanged

Defense: 10 + ½ (Armor AC - 10) (round down) + proficiency + DEX + shield + weapon magic bonus, etc (i.e. half armor effect, replace with proficiency)

Damage: Unchanged

Damage Reduction: Damage reduced by ½ (Armor AC - 10) (round up) (note: shield, DEX, etc do not contribute)

Impact for Creature Stats: More complex adjustment

- Attack bonus: Unchanged

- Defense: AC + (Attack Bonus - STR)* - Damage reduction (see below)

- Damage Reduction: ½ (Armor AC - 10) (round up) (note: remove DEX, shield bonus, etc from AC first)

(* Attack Bonus - STR approximates Proficiency Bonus. Or simply derive from Challenge Rating using p274 of the DMG, which is basically the same as treating Challenge Rating as Character Level: Challenge <4 = Proficiency Bonus 2, Challenge 4-7 = Proficiency Bonus 3, etc)

Option 4: The Purist - Separate Armor & Defense

The purist approach re-phrases combat as an Attack vs Defense roll that is all about a contest of skill, and a Damage - Armor roll that is all about armor's ability to reduce damage. The influence of other role-play systems must be acknowledged here, including the underrated Dragon Warriors that was little known outside of the UK. The magnitude of damage reduction to use here is debatable but the reality is that a one-handed weapon had very little chance of injuring a mobile medieval knight in undamaged full plate armor, so the easiest approach is to use (Armor AC - 10).

If these were the only changes, then combat damage would be greatly reduced (esp. for those with multiple smaller attacks). So, to maintain balance, there are two sub-options: one that simply doubles the damage that does get through armor (note do not double additional damage - e.g. Sneak Attack, Smite, etc); or one that gradually overcomes damage reduction, depending on the success margin of the Attack vs Defense roll. The latter could also be applied to the damage reduction presented in the previous options (Options 2 & 3 above) but it is only recommended for those who enjoy intricate combat systems.

Attack bonus: Unchanged

Defense: 10 + proficiency + DEX + shield + weapon magic bonus, etc (i.e. remove armor, replace with proficiency)

Damage: Two sub-options:

- Simplest: Roll as usual but any damage that does get thorough armor is doubled

- or More complex: Ignore one point of damage reduction for every point of the success margin in the Attack vs Defense roll

Damage Reduction: Damage roll reduced by (Armor AC - 10) (note: shield, DEX, etc do not contribute)

Impact for Creature Stats: More complex adjustment

- Attack bonus: Unchanged

- Defense: (Attack bonus - STR)* and move DEX/shield from AC (rough alternative is to just use Attack bonus or ½ (AC - 10))

- Damage Reduction: (AC - 10) and move DEX/shield from AC (rough alternative is to just use ½ (AC - 10))

(* Attack Bonus - STR approximates Proficiency Bonus. Or simply derive from Challenge Rating using p274 of the DMG, which is basically the same as treating Challenge Rating as Character Level: Challenge <4 = Proficiency Bonus 2, Challenge 4-7 = Proficiency Bonus 3, etc)

Option 5: Harmonized (The Grand Unified Theory)

Each of the above have their pros and cons. The most complete options are more complex to adjust existing material to. Damage reduction has perhaps a disproportionate effect on those making multiple attacks of smaller amounts and may affect game balance. (One alternative option for addressing the last issue is presented elsewhere on dandwiki: Armor and Damage Redux). The final option presented here aims to bring it all together in one simple package, most easily integrated with core 5e rules. Defense is added in the form of the Proficiency bonus, as in the other options. Damage modification is addressed differently: as a proportional effect integrated into the Attack vs Defense roll. Essentially armor reduces the chance of being hit and, if hit, reduces damage from a marginal hit. In contrast, a hit by a large margin (either from a large difference in skill, or a large deficit in armor, or an immobilized target where defense and armor are bypassed, etc) does critical damage. (PS Inspiration credit here to the swashbuckling options in Dragon 232 ...back in 1996).

Attack bonus: Unchanged

Defense: AC + proficiency -4 (i.e. just add proficiency bonus but compensate with a fixed -4) (note: a weapon may only rarely have a bonus to Defense, as this would create an imbalance with magical bonuses from both armor and weapon)

Damage: Depends on margin of success on Attack roll (and consider not allowing DEX or CHR to substitute for STR)

- Succeed by 0-2: Half damage (round up), including half of any bonuses etc

- Succeed by 3-5: Unchanged

- Succeed by 6-8: Double damage dice (but not bonuses etc)

- Succeed by >8 or where a hit is automatic: Maximum value of double damage dice (bonuses etc not doubled)

- Critical: Maximum damage in the above categories (this replaces the standard 5e critical damage system)

Damage Reduction: Unchanged (see above instead)

Impact for Creature Stats: Easy adjustment

- Attack bonus: Unchanged

- Defense: AC + (Attack Bonus - STR)* - 4 (a quick alternative is just AC -2 for low level creatures, to +2 for high level creatures)

- Damage Reduction: Unchanged (see above instead)

(* Attack Bonus - STR approximates Proficiency Bonus. Or simply derive from Challenge Rating using p274 of the DMG, which is basically the same as treating Challenge Rating as Character Level: Challenge <4 = Proficiency Bonus 2, Challenge 4-7 = Proficiency Bonus 3, etc)

A footnote: You may have noticed that the damage reduction from a marginal hit is technically more of a change in threshold for this "marginal hit" via the influence of AC on the Attack roll. The actual "marginal" zone applies to all armor states - from unarmored to full plate. For those who feel this is too simple, you can consider half damage for a success margin of 0-2 for heavy armor, 0-1 for medium armor, 0 for light armor and not at all for unarmored, but it is recommended not to apply that scaling to the normal or double damage ranges.

Epilogue

Play-testing and feedback is the lifeblood of the homebrew. Please leave comments in the discussion page. _RM_

UK English title: Combat Realism - Defence and Armour Options

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