Damage Reduction

Damage Reduction (DR) is a measure of how much of an attack's damage a character can soak up before losing hit points. The DR value is subtracted from each incoming hit, to a minimum of zero. If you have a DR of 10 and get hit for 9 points of damage, you take no damage at all. If you have a DR of 10 and get hit for 15 points of damage, you only take 5 points of damage. DR applies only to physical weapon damage, although there is a similar concept of Energy resistance that can apply to other damage sources.

Player characters (but not monsters, apparently) can gain "Active DR" when they are holding down shift to block. Active DR is a hidden quantity, but Passive DR is easily visible on the character sheet. Multiple DR entries will be listed, and only the highest one which is not bypassed by a particular attack's properties (like Adamantine) applies.

Active DR stacks with passive DR when actively blocking.

Active DR Formula
Base active DR = Passive DR + (with shield) = [(BAB / 2) + 2 + Shield DR rating + Shield Enhancement Bonus + Shield Mastery Feats + Shield Mastery Enhancements] versus Ranged / 2 (with TWF) = [(BAB / 3) + 2 + Two-weapon Blocking Feat] versus Ranged / 4 (with Other*) = [(BAB / 5) + 1 + (No Feats)] *Other is THF, Single weapon & no shield, or Unarmed and gives full DR versus Ranged attacks.

Active DR bonuses
The following Shield Mastery feats and enhancements are added onto the above base active DR value. They all stack.
 * Shield mastery +3
 * Improved shield mastery +3
 * Dwarven shield mastery +1, 2 or 3 (for levels I, II, and III of the enhancement)
 * Two-weapon blocking

Example - A level 8 fighter with the regular and Improved shield mastery feats, actively blocking with a +4 Heavy Adamantine Shield would have the following:

Active Blocking DR vs. melee = 1 +(8/2)+ 2 + 2 + 4 + 6 = DR19/- Active Blocking DR vs. ranged = 1 + [(8/2)+ 2 + 2 + 4 + 6]/2 = DR10/-

Passive DR bonuses
Passive DR can be provided from many sources, including:
 * Warforged Adamantine Body, Improved DR Feats, or Warforged Improved DR enhancements
 * Barbarians get +1 DR/- at levels 2, 5, 8, 11, 14 and a +1 Enhancement available at levels 4 and 7. Barbarian DR stacks with Active Blocking DR.
 * Adamantine Armor (1 from shields or light armor, 2 from medium armor, and 3 from heavy armor). Armor DR stacks with Active Blocking DR.
 * Ironskin Chant (DR5/-) song from Warchanter Bard. Ironskin Chant DR stacks with Active Blocking DR.
 * The Stoneskin spell (DR 10/Adamantine), Angelskin spell (DR5/Evil)
 * magical items of Invulnerability (DR 5/Magic), or of Axeblock, Hammerblock, and Spearblock
 * certain named items, like the Bloodrage Symbiont or Golden Greaves

These passive DR sources do not stack: only the highest DR not overcome by the attack type is taken into account. But, if one type of DR is bypassed, a different source, lower value DR can apply.

Example - A Warforged Fighter has Adamantine Body and DR6/Adamantine and also has the temporary Ironskin Chant song DR5/- from a Bard in the party. He is hit with an Adamantine attack/weapon, bypassing his DR6/Adamantine. But, he receives DR5/- from the Ironskin Chant.

Armor DR, Barbarian innate DR, and Ironskin Chant do stack with blocking DR. This is not the case for Warforged Adamantine DR.

DR Aspects
While Active DR applies universally to all weapon attacks, Passive DR may be bypassed by the properties of a particular attack. Some forms of DR are vulnerable to materials (like Adamantine or Silver), alignments (like Chaos or Good), or just "magic". In this case, the property which bypasses that DR is listed after the number on the character sheet, in the form of "DR 6/Adamantine" or "DR 5/Evil". If there is no property which can bypass the DR, a "-" is listed instead.

Monster DR
Currently, DDO is known to include monsters requiring adamantine (Iron Golems), bludgeon (Skeletons and Clay Golems), and slashing (Zombies) weapons to penetrate their damage reduction. DDO also includes special weapons made from materials such as adamantine, mithril, darkwood, cold iron, silver, and byeshek.

Some monsters are vulnerable to magic weapons only. Any weapon with at least a +1 magical enhancement bonus on attack and damage rolls overcomes the damage reduction of these monsters.

Some examples include:
 * Clay Golems require Bludgeoning and Adamantine weapons
 * Flesh Renders require Good Aligned and Cold Iron weapons
 * Rakshasa require Good Aligned and Piercing weapons
 * Ghostly Skeletons require Good Aligned weapons
 * Iron Golems and Flesh Golems require Adamantine weapons
 * Skeletons require Bludgeoning weapons
 * Vampires require Silver weapons
 * Zombies require Slashing weapons