Elemental

Separate the final Hit into Fire, Cold, and Lightning components, apply every modifier whose full wording matches each component, then mitigate each type with its corresponding Resistance. Exposure changes the target's actual Elemental Resistances, while Penetration only treats Resistance as lower for the attacker's Hits and normally cannot take it below 0%.

Three damage types

Elemental Damage means Fire, Cold, and Lightning Damage. It is a damage-type family, not a source or delivery method, so an Attack, Spell, Hit, or damage over time effect can be Elemental when its own damage type and wording match.

One modifier, matching components

A global increased Elemental Damage modifier applies once to every final Fire, Cold, or Lightning component it matches. It does not become three separate multipliers merely because a Hit contains all three elements, and it remains additive with other applicable increased and reduced damage modifiers.

Weapon damage and global scaling

Flat Fire, Cold, or Lightning Damage added locally to a Martial Weapon is included in that weapon's displayed damage. The ordinary increased Elemental Damage with Attacks weapon modifier is global, so it does not change the displayed weapon damage and is added to other applicable increased damage modifiers during the Attack calculation.

Conversion and final type

Conversion inherent to a Skill happens first and conversion from other sources happens second. Converted damage scales with its new final type and no longer with its old type. Damage over time cannot be converted.

Elemental Resistances

Fire, Cold, and Lightning Damage are mitigated separately by Fire, Cold, and Lightning Resistance. The default maximum Resistance is 75%, maximum Resistance cannot be raised above 90%, and a negative Resistance increases damage taken from that type.

Exposure changes the target

Exposure is a debuff that lowers the target's Total Elemental Resistances by 20% for 4 seconds by default and can make them negative. Exposure has 15% less effect on Magic monsters, 30% less effect on Rare monsters, and 50% less effect on Unique monsters unless a source states another rule.

Penetration is Hit only

Resistance Penetration does not change the target's stored Resistance. It treats the corresponding Resistance as lower only when calculating damage from the source's Hits, after other changes to the target's Resistance, and normally cannot penetrate below 0%.

Fire, Flammability, and Ignite

A Fire Hit now inflicts Flammability before that same Hit checks whether it Ignites. Flammability supplies Ignite chance and stacks to 100%; it does not increase Ignite damage. If Ignite is applied, its base Magnitude is Fire damage per second equal to 20% of the qualifying Fire damage from the Hit for 4 seconds by default.

Cold, Chill, and Freeze

Cold Hits Chill by default and contribute to Freeze Buildup, but cannot build Heavy Stun. A Chill below 30% is ignored, while Freeze occurs after enough Freeze Buildup and prevents the target from moving or acting for 4 seconds by default.

Lightning and Shock

Lightning Damage from Hits contributes to Shock chance. By default, a Hit gains 1% chance to Shock for each 4% of the target's Elemental Ailment Threshold dealt as Lightning Damage, and Shock makes the target take 20% increased damage while active.