Fortification

Fortification represents a percentage chance to negate a critical hit or sneak attack. When a critical hit is negated, damage is applied normally rather than at the critical hit multiplier. Fortification items stack with racial fortification of Warforged. Standard fortification items provide enhancement bonuses to fortification and do not stack with each other. Likewise, two exceptional fortification items don't stack, as they provide insight bonuses to fortification and insight bonuses do not stack. One regular fortification (enhancement bonus) and one exceptional fortification (insight bonus) item will stack with each other because they are different bonus types.

Since Update 13, monsters with sneak attack dice are able to bypass some of the player fortification equal to monsters' Challenge Rating. E.g.:

• If a CR 1 Kobold Sneak attacks someone with 50% fortification, the Kobold Sneak has a 51% chance to normally conduct a critical hit or sneak attack.
• If a CR 20 Lava Mephit attacks someone with 100% fortification, the Lava Mephit has a 20% chance to normally conduct a critical hit or sneak attack.
• If a CR 54 Sellsword Footpad attacks someone with 150% fortification, the Sellsword Footpad has a 4% chance to normally conduct a critical hit or sneak attack.
• If a CR 29 Earth Elemental attacks someone with 125% fortification, it is still going to have a 0% chance to critically hit or sneak attack, as it has no sneak attack dice. [1]

Light Fortification

Found on: Armor Belts Rings Shields as a Suffix

Base price modifier: +1

Effect: Grants a +25% enhancement bonus to fortification, which protects against critical hits and sneak attacks.

Moderate Fortification

Found on: Armor Belts Rings Shields as a Suffix

Base price modifier: +3

Effect: Grants a +75% enhancement bonus to fortification, which protects against critical hits and sneak attacks.

Heavy Fortification

Found on: Armor Belts Rings Shields as a Suffix

Base price modifier: +5

Effect: Grants a +100% enhancement bonus to fortification, which protects against critical hits and sneak attacks.

Exceptional Fortification (10%)

• Found on:
  • Toven's Hammer
  • Stalwart Trinket
  • Greater Stalwart Trinket
  • The Disciplinator
  • Sustaining Symbiont

Effect: Grants a +10% insight bonus to fortification, which protects against critical hits and sneak attacks. Note this bonus type does not match the name of the enchantment any longer.

Exceptional Fortification (25%)

• Found on:
  • Omniscience

Effect: Grants a +25% insight bonus to fortification, which protects against critical hits and sneak attacks. Note this bonus type does not match the name of the enchantment any longer.

Exceptional Fortification (50%)

• Found on:
  • Livewood Core (Level 24)
  • Leaves of the Forest (Level 24)

Effect: Grants a +50% insight bonus to fortification, which protects against critical hits and sneak attacks. Note this bonus type does not match the name of the enchantment any longer.

Construct Fortification (10%)

• Found on:
  • Docent of the Claw
  • Dragontouched Docent
  • Quorforged Docent of Battle
  • Docent of the Flames
  • Quorforged Docent of Battle (unsuppressed)

Effect: Grants a +10% insight bonus to fortification which protects against critical hits and sneak attacks. This enchantment is essentially identical to Exceptional Fortification (10%) and therefore does not stack with it.

Stacking Fortification (25%)

• Found on:
  • Fabricator's Bracers and Fabricator's Gauntlets worn as set, once Nearly Finished is unlocked.

Effect: Grants a +25% untyped bonus to fortification, which protects against critical hits and sneak attacks. Untyped bonuses stack.

Brace for Impact (+20%/+40%)

• Found on
  • Unyielding Sentinel

Effect: Passive Bonus: [+20/40]% untyped bonus to fortification. +[1/2] reflex/fort/will saves. Tier 1 Epic Destiny ability that can be purchased twice for a total of 40% fortification. Untyped bonuses stack.