Defense Bonus

The following is derived from material located here.

In the standard d20 rules, a character’s skill at attacking gets better as he goes up in level—but not so his skill at avoiding attacks. Characters rely on armor and an ever-growing collection of magic items to protect them in combat. But what about campaigns in which it’s not common or appropriate for characters to go everywhere in full plate?

This variant system is particularly appropriate for swashbuckling or stealth-based campaigns, for settings in which firearms are common, for seafaring campaigns (in which the characters would rather not wear armor for fear of drowning), or any other setting in which armor is not worn on a day-to-day basis—even by adventurers.

Metagame Analysis: Class Defense
Using the defense bonus variant in your game means that sometimes, at least, characters won’t want to wear armor—their defense bonus provides them with free protection that’s just as good as armor. Funds that would otherwise be spent improving a character’s armor can instead be spent on other gear, which means the characters’ power level will increase slightly.

Characters may still desire the properties of a specific kind of magic armor or of armor special abilities. Be prepared to create new magic items, such as cloaks, robes, vests, or vestments, to support those desires.

Clearly, the class defense system is best for characters who must choose between going unarmored and risking arcane spell failure—sorcerers and wizards in particular. Classes limited to light or medium armor also flourish under this system, since they can multiclass to gain the benefit of a higher defense bonus.

Spells that affect metal are less useful under this system, since metal armor is less common.

Touch AC only incorporates 1/2 of your defense bonus (rounded down).

The Class Defense Bonus

In this variant, every character has a defense bonus based on his character level. The defense bonus applies to Armor Class. However, it does not stack with the character’s armor bonus. A character wearing armor gains his armor bonus (including any enhancement to that bonus) or his defense bonus—whichever is higher—but not both. The defense bonus stacks with all other bonuses to AC, including the character’s shield bonus, natural armor bonus, and so forth.

Unlike an armor bonus, a defense bonus does improve a character’s AC against touch attacks, but is not counted for their flat footed AC.

A character’s defense bonus is derived from his character level and class, as shown on Table: Defense Bonus. For a multiclass character, use the highest defense bonus of those offered by the character’s classes. For example, a 2nd-level barbarian has a defense bonus of +4. If the character gains a level of cleric (becoming a 2nd-level barbarian/1st-level cleric), her defense bonus increases to +7, because the cleric’s +7 at 3rd character level is better than the barbarian’s +5 at 3rd character level.

Table: Defense Bonus
Level A1 B2 C3 D4
1st +2 +3 +4 +6
2nd +2 +3 +4 +6
3rd +3 +4 +5 +7
4th +3 +4 +5 +7
5th +3 +4 +5 +7
6th +4 +5 +6 +8
7th +4 +5 +6 +8
8th +4 +5 +6 +8
9th +5 +6 +7 +9
10th +5 +6 +7 +9
11th +5 +6 +7 +9
12th +6 +7 +8 +10
13th +6 +7 +8 +10
14th +6 +7 +8 +10
15th +7 +8 +9 +11
16th +7 +8 +9 +11
17th +7 +8 +9 +11
18th +8 +9 +10 +12
19th +8 +9 +10 +12
20th +8 +9 +10 +12
  1. Use column A for monk, sorcerer, or wizard.
  2. Use column B for bard, ranger or rogue.
  3. Use column C for barbarian or druid.
  4. Use column D for cleric, fighter or paladin.

Defense Bonuses For Other Classes
For classes not mentioned here, determine a character’s class defense bonus based on the armor proficiency granted by the class (and only that gained from the class—you can’t take an Armor Proficiency feat to improve your defense bonus). Consult Table: Defense Bonus For Other Classes; the defense bonus progression refers to the indicated column on Table: Defense Bonus.

Table: Defense Bonus For Other Classes
Armor Proficiency Defense Bonus Progression
None Column A
Light Column B
Light and medium Column C
Light, medium, and heavy Column D

Monster Defense Bonuses

Monsters do not have inherent defense bonuses unless they also have levels in a class or are normally proficient with armor. When calculating a monster’s defense bonus to AC, do not include the monster’s base HD or level adjustment (if any).

For example, a typical green dragon, gargoyle or black pudding has no class levels and is not proficient with any armor. Such creatures do not get a defense bonus.

If a creature is proficient with one or more types of armor, however, it gains a defense bonus. See Table: Creature Defense Bonuses.

Table: Creature Defense Bonus
Armor Proficiency Defense Bonus
None +0
Light +1
Light and medium +2
Light, medium, and heavy +4

If a creature has levels in a class, it gains a defense bonus just like any other character with a class. This bonus does not stack with any defense bonus the creature may have from armor proficiency.

For instance, giants are considered proficient with whatever type of armor (light, medium or heavy) they are described as wearing. Hill giants, described as wearing hide armor, therefore have a +2 defense bonus (hide armor is medium armor). Since this is lower than the +3 bonus of hide armor, the typical hill giant probably prefers to wear his armor. A 1st-level hill giant barbarian, however, would have a defense bonus of +4, and would benefit from discarding his hide armor (though he’d gain a higher armor bonus by putting on chainmail or a breastplate).

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