See the main Damage Types article.
To ignore armor means to set the Armor Effect, a multiplier in calculating damage, to 1. Offensive skills and actions that ignore armor take away the same amount of health on all targets, regardless of the caster's character level and target's armor. It is generally believed that when armor is ignored, armor penetration isn't relevant (for both technical and semiotic reasons).
Some skills explicitly state whether they deal armor ignoring damage or not.
- Obsidian Flame specifically mentions that it ignores armor.
- Judge's Insight states, by way of implication, that attacks under this enchantment will not deal armor ignoring damage.
Most damage dealing skills, however, do not explicitly indicate whether the damage dealt will ignore armor. Many people prefer a logical grouping of skills based on skill properties and descriptions, expecting that whether a skill deals armor ignoring damage or not is governed by observable features of the skill description itself. One major point of view uses damage type, while another refers to the damage actuator mentioned in the skill descriptions. Both these prescriptive categorizations have flaws.
Because the number of skills in the game is fixed, one can simply enumerate all skills that cause armor ignoring damage. Although such an enumeration would be a completely faithful descriptive account of the game, as far as categorization goes it is unhelpful. It is certainly possible that there is no definitive pattern, and the developers simply set for each skill whether or not it will ignore armor. There may be guidelines that usually apply, but these guidelines are only as valid as Arena Net chooses to make them, and there can always be exceptions.
The following subsections outline the two major schools of thought regarding the classification problem, together with a summary of the major criticisms.
Classification by damage type
This school of thought says that the type of damage caused by a skill or action determines whether the damage will be armor ignoring or not. Specifically,
- Ignores armor: shadow damage and damage with no specified type
- Does not ignore armor: physical damage, elemental damage, dark damage, and chaos damage
- Holy damage ignores armor if it is caused by a skill, but is affected by armor if it is caused by an attack.
The major advantage is that using this categorization, players can quickly determine whether or not a skill ignores armor.
Dark damage is similar to shadow damage. Holy damage used to have a similar split that was since removed, implying that it is the same type of damage with the skill providing the armor-ignoring function.
This categorization also has the following exceptions.
- Dust Trap deals earth damage but ignores armor. Dust Trap has additional bug regarding its damage type.
- Whirling Defense deals piercing damage but ignores armor. Whirling Defense has additional bug regarding its damage type.
Supporters of this categorization theory claim that these skills are simply anomalous, possibly a result of programming bugs.
Classification by damage actuator
This theory holds that whether or not a skill ignores armor depends on the exact words describing how the damage is dealt.
- Verbs such as "deal" and "suffer" in the skill description signal armor ignoring damage.
- Verbs such as "take" and "struck for" in the descriptions signal armor respecting damage.
This theory typically states only a two-verb comparison, making the theory less than complete. No one has presented a complete theory that takes all (or even a majority) of the skills into account.
The existence of exceptions is probably why a complete theory has not been proposed.