Bonuses apply to things like your attack roll, damage roll, skill checks, etc. An example is a +2 feat bonus to attack rolls, +1 power bonus to AC, or the Dwarf's +5 racial bonus vs poisons. A bonus is always beneficial, increasing the chances of success or the degree of success.
Here are some examples of each:
- A dwarf gets a +5 racial bonus vs poisons.
- Fighters get a +1 bonus to attack rolls with their chosen weapon style (one-handed or two-handed).
- The pit fighter's Armor Optimization class feature gives a +1 untyped bonus to AC as long as you are wearing any type of armor.
- The paladin Channel Divinity power divine strength adds his Strength modifier as extra damage to his next attack.
- A cleric's bless prayer adds a +1 power bonus to attack rolls of all allies in range for the rest of the encounter.
- Blade Opportunist is a feat that gives a +2 bonus to opportunity attack attack rolls with a heavy blade or a light blade.
- Combat advantage is a circumstance that gives a +2 bonus to the attack roll against a target over whom you have gained some specific advantage, whether because he dropped his guard, fell prone, etc.
- An enhancement bonus on a weapon or implement can add its bonus to attack and damage rolls for powers that have the weapon or implement keyword. For example, a longsword +3 adds 3 to the attack roll and 3 to the damage roll of melee weapon attacks.
The type of bonus is important. There are feat bonuses, racial bonuses, power bonuses, etc. Any bonus that isn't specifically given a type is an untyped bonus.
Why does this matter? Because bonuses of the same type do not stack! The only exception to this is untyped bonuses, which always stack (even with each other). If you have multiple bonuses of the same type, you only get to use the highest one.
A level 5 dwarven character has:
- Dwarven Weapon Training, which gives a +2 feat bonus to damage rolls with axes.
- Weapon Focus in Axes, which gives a +1 feat bonus to damage rolls with axes.
- Power Attack, which gives a +2 damage roll bonus in exchange for a -2 attack roll penalty when active. This bonus is untyped.
- Villain’s Menace, which he used at the beginning of the encounter against this enemy to gain a +4 power bonus to damage.
Because the bonuses from dwarven weapon training and weapon focus are both feat bonuses, they do not stack with each other. Thus the higher +2 bonus takes precedence. The Power Attack bonus does stack because it is untyped, and the power bonus from Villian's Menace also stacks because there are no other power bonuses to conflict with. The character gains a total bonus of +8 to damage rolls.
Note that in this example, this character should probably not learn Weapon Focus yet because Dwarven Weapon Training is more beneficial early on and the two do not stack. Later, in the Epic Tier, Weapon Focus will actually add +3 damage and exceeds Dwarven Weapon Training. At that point the character could swap the two feats using retraining.
List of the most common bonus types
Armor Bonus: This bonus is obtained by wearing armor. It primarily adds bonus to AC. At higher levels the AC bonus is higher, and the armor can sometimes also grant an armor bonus to NAD. This is not to be confused with the enhancement bonus to AC and NAD from magic armor.
Enhancement Bonus: This bonus is obtained from magic armor, magic weapons and implements, and magic items occupying the neck item slot. Magic armor gives a bonus to AC, magic weapons and implements give a bonus to attack rolls and damage rolls, and magic items in the neck item slot grant a bonus to NAD. An adventurer can benefit from one enhancement bonus for each of the three subcategories as they apply to different scores and rolls.
Feat bonus: This bonus is obtained from having a feat.
Item bonus: Granted by a magic item, this bonus is gained by wielding or wearing an item.
Proficiency bonus: Gained by being proficient in a weapon, it adds to attack rolls when an adventurer wields the weapon while using a power with the weapon keyword.
Untyped bonus: Some bonuses have no type, and usually stack with other bonuses. Untyped bonuses from the same game element (such as a power or a feat) do not stack with itself.
Penalties: Penalties do not have types, and stack unless they are from the same game element.
Read Carefully: Common Mistakes with Bonuses
It's important to read a bonus's description carefully and understand the rules that surround its use. I'll use damage bonuses as an example because they are common and examples of confusing situations are readily available.
Case Study: Weapon Focus
Weapon Focus is a feat that specifically states that it adds damage to damage rolls. Thus, if an power says "Hit: 1[W] + strength modifier" then the weapon focus bonus applies when you hit the target. Likewise, if a power says "Miss: Half damage", you perform the damage roll as normal (adding all applicable modifiers) and then divide the result in half.
Weapon Focus does not apply to static (constant, non-roll) damage, however. For example, Cleave says "Hit: 1[W] + Strength modifier damage, and an enemy adjacent to you takes damage equal to your Strength modifier". In this case, Weapon Focus adds to the damage dealt to the primary target, but not to the adjacent enemy. This is because dealing damage equal to your Strength modifier is a constant amount. You don't roll a die to figure out how much damage that is, it's just a set amount. Thus, the adjacent enemy would receive only your strength modifier in damage, without the weapon focus bonus.
Reaping Strike is similar. Instead of saying "Miss: Half damage" it says "Miss: Half Strength modifier damage. If you’re wielding a two-handed weapon, you deal damage equal to your Strength modifier.". Whether you're wielding a two-handed weapon or not, Reaping Strike still deals constant damage on a miss, and thus forfeits bonuses like the one from Weapon Focus when dealing its miss damage.
Case Study: Dirty Fighting
The whole situation changes with bonuses like Dirty Fighting. It is a class feature of the Pit Fighter paragon path, gained at level 16. It says "Increase the damage you deal when using a weapon by a number equal to your Wisdom modifier (minimum +1)".
Note that this bonus does not say it increases damage rolls. It increases the damage you deal with a weapon. This means that any attack you use that has the Weapon keyword qualifies, and the bonus applies to each separate instance of damage in that power. Let's again use cleave as an example.
Cleave has two separate instances of damage: 1) The damage roll against the primary target and 2) the static damage against the adjacent enemy. Clearly Dirty Fighting will affect the damage roll. However, because of its specific wording, it also applies to the damage dealt to the adjacent enemy!
Example 1: Cleave
Griff the level 18 dwarven fighter has 21 Strength and 20 Wisdom, and wields a battleaxe. He has learned Weapon Focus for axes and has gained Dirty Fighting from taking the Pit Fighter paragon path. He uses cleave against an enemy and hits. Assuming no other bonuses apply:
- The primary enemy takes 1d10(weapon) + 5(strength mod) + 2(weapon focus) + 5(wisdom mod) damage, for a total of 1d10 + 12.
- The adjacent enemy takes 5(strength mod) + 5(wisdom mod) damage, for a total of 10.
Example 2: All Bets are Off
The pit fighter's all bets are off power is another perfect example of reading carefully and knowing how to handle vague or obscure rules. Dirty Fighting applies its damage bonus to all fighter and pit fighter weapon attacks, which means all fighter and pit fighter attack powers with the weapon keyword.
So, the Dirty Fighting bonus applies to both all bets are off attacks, primary and secondary, because both occur within the same power that has the weapon keyword. Even though the flavor text for all bets are off implies that the second attack is punching the target, that's not how the rules apply to the attack. Even without the [W] symbol, the all bets are off secondary attack is still a weapon keyword attack.
Note: This conclusion was verified by the Wizards of the Coast support staff, though many players would not agree with it if they did not know this. It's a very unintuitive and far from obvious situation that has confused many players. For this reason, some DMs and players prefer to rule differently for flavor reasons or their own interpretation. That's fine -- it's what Rule 0 is for!
Thus, if the character in example 1 hit with both attacks in dirty fighting:
- Primary Attack would deal 2d10(weapon) + 5(strength mod) + 2(weapon focus) + 5(wisdom mod), for a total of 2d10 + 12
- Secondary Atack would deal 1d6 + 5(strength mod) + 2(weapon focus) + 5(wisdom mod), for a total of 1d6 + 12
Don't Get Carried Away
So Dirty Fighting applies damage to nearly everything, but not to attacks that don't have the weapon keyword (such as wizard spells). It's a good idea to look for these special cases where a bonus won't do what you might think it does at first glance. Give things a good, close look... you may be surprised.
That said, there are very few damage bonuses that act like Dirty Fighting. Most apply to damage rolls. Some example bonuses that do not require a damage roll are:
- Dirty Fighting (pit fighter class feature)
- Extra Damage Action (pit fighter and tactical warpriest paragon path feature)
- divine strength (granted by paladin Channel Divinity class feature)
Don't assume too much or too little. When in doubt, grab the Player's Handbook and check.