If a player is wearing at least 3 pieces of warpriest armour when damaged, there's a chance that damage would be reduced.
Each piece of Warpriest armour increases the chance of the passive effect occurring by 1%, starting at 3% for 3 pieces. The maximum chance the effect can occur is 6%, if 6 total pieces of Warpriest armour are worn.
Damage is reduced to an amount equal to 10% of the initial damage minus the total number of Warpriest armour pieces worn at the time. If all 6 pieces of Warpriest armour is worn, the player will only take 4% of the initial attack.