Sanctum of Thought
30% increased Armour
20% reduced Effect of Curses on you 
The bonus granted by this passive skill causes the character to take reduced extra damage from critical strikes. This is a modifier on the percentage of damage over 100% that an enemy inflicts with a critical strike on the character.
m be the enemy's critical strike multiplier and let
R be the sum of the
r's in You take
r% reduced Extra Damage from Critical Strikes modifiers being applied to the character. The enemy's effective critical strike multiplier
E is given by
E = 100 + (m - 100) * (1 - R/100)
m = 150% and
R = 20%, then
E = 100 + (150 - 100) * (1 - 20/100) = 140%
The enemy's effective critical strike multiplier is 140%, thus the extra critical strike damage is reduced by 20%, but the total damage of the critical strike has only been reduced by 6.67%.
The You take 20% reduced Extra Damage from Critical Strikes modifier on Sanctum of Thought stacks with the You take 30% reduced Extra Damage from Critical Strikes modifier on Belt of the DeceiverBelt of the Deceiver
Heavy BeltRequires Level 20+(25-35) to Strength(15-25)% increased Global Physical Damage
You take 30% reduced Extra Damage from Critical Strikes
+(30-40) to maximum Life
+(10-15)% to all Elemental Resistances
Nearby Enemies are IntimidatedIn battle, virtue matters not.
The unique modifier Take no Extra Damage from Critical Strikes on The Brass DomeThe Brass Dome
Gladiator PlateQuality: +20%
Movement Speed: -5%Requires Level 65, 177 Str30% reduced Chance to Block Attack and Spell Damage
(600-650)% increased Armour
10% reduced Movement Speed
50% increased Shock Duration on you
Take no Extra Damage from Critical StrikesThe turtle's shell one day becomes its tomb. renders Sanctum of Thought redundant.