A damage increase effect causes the target to inflict additional damage in combat with any weapon. This effect stacks with itself and is added to the damage inflicted by the weapon itself. The increased damage is multiplied on a critical hit. This effect is created in a script by the command EffectDamageIncrease().
Physical damage increase effects are converted to the wielded weapon's base damage type and are subject to damage reduction, damage resistance and damage immunity as usual. Other damage types ignore the damage resistance and immunity of creatures, but are individually subject to the hardness of a placeable.
There is a cap of 100 damage per hit (including critical hits) applied to the combined damage from physical damage increase effects and physical damage bonuses on a weapon. (Other sources of physical damage — such as the weapon's base damage — are not included in this cap.) There is a cap of 1000 damage per hit (not including critical hits) applied to the total of all non-physical damage increase effects (regardless of type).
Examples[]
Consider a character with 14 strength, a +20 enhancement halberd (with no other properties), a +20 piercing damage increase effect, a +10 divine damage increase effect (from divine might ), and a +5 magical damage increase effect (from divine favor).
If he scores a critical hit on a placeable with 20 hardness, then the +20 from the enhancement is combined with the +20 from the damage effect and is multiplied by 3 to get 120, but only makes 100 damage because of the cap. Thus he scores 100 + 9 (two-handed strength bonus) + 3d10 (base weapon damage) - 20 (hardness) = 89 + 3d10 physical damage. He also deals 30 divine - 20 (hardness) = 10 divine damage. He deals 0 magical damage, as 3*5 magical damage is less than the placeable's hardness. Thus the combat log will show ({89 + 3d10} physical, 10 divine, 0 magical) along with three resistance lines indicating the placeable absorbed 20, 20, and 15 damage.
If he scores a non-critical hit on a monster with 100% immunitiy to divine and piercing, 20 resistance to piercing, and 100% vulnerability to magic: The physical damage would bypass the piercing immunity and resistance as the halberd is both piercing and slashing, the divine damage would stay the same as it was from the damage increase effect, and the magical damage would not increase as it came from the damage increase effect. The combat log will show ({43 + 1d10} physical, 10 divine, 5 magical) and there will be no lines showing what the immunity/resistance absorbed since they were all bypassed.