diff --git a/Modules/Data/Constants.lua b/Modules/Data/Constants.lua
index 7f424a18..ee2db730 100755
--- a/Modules/Data/Constants.lua
+++ b/Modules/Data/Constants.lua
@@ -1,3 +1,6 @@
+local IsTBC = ECS.IsTBC
+local IsWotlk = ECS.IsWotlk
+
 ---@class Data
 local Data = ECSLoader:ImportModule("Data")
 
@@ -79,6 +82,65 @@ Data.Aura = {
         [17800] = (ECS.IsWotlk and -5 or nil), -- Shadow Mastery 5/5
         [22959] = (ECS.IsWotlk and -5 or nil), -- Improved Scorch
     },
+    ---@type table<Bitmask>
+    HitReductionMelee = {
+        [0] = {
+            [35346] = 50, -- Warp
+            [54956] = 100, -- Impaling Charge
+            [59827] = 100, -- Impaling Charge
+            [50240] = 200, -- Evasive Maneuvers
+            [2651] = (IsTBC and 20 or nil), -- Elune's Grace
+            [455868] = -1, -- Revealed Weakness
+            [445875] = -100, -- Gloom
+            [460725] = -100, -- Gloom
+        },
+        [127] = {
+            [54603] = 25, -- Serpent's Agility
+        },
+        [95] = {
+            [50280] = 20, -- Oily Coat
+        },
+        [14] = {
+            [47000] = (IsWotlk and 15 or 13), -- Improved Blink
+            [46989] = (IsWotlk and 30 or 25), -- Improved Blink
+        },
+    },
+    HitReductionRanged = {
+        [50280] = 20, -- Oily Coat
+        [455868] = -1, -- Revealed Weakness
+        [2651] = (IsTBC and 20 or nil), -- Elune's Grace
+        [26669] = 25, -- Evasion
+        [47000] = (IsWotlk and 15 or 13), -- Improved Blink
+        [46989] = (IsWotlk and 30 or 25), -- Improved Blink
+        [54603] = 25, -- Serpent's Agility
+        [67801] = 100, -- Deterrence
+    },
+    ---@type table<Bitmask>
+    HitReductionSpell = {
+        [0] = {
+            [54603] = 25, -- Serpent's Agility
+            [50280] = 20, -- Oily Coat
+            [445875] = -100, -- Gloom
+            [460725] = -100, -- Gloom
+            [56673] = -100, -- Fight Wyrm
+        },
+        [127] = {
+            [33196] = (IsWotlk and -1 or nil), -- Misery
+            [33197] = (IsWotlk and -2 or nil), -- Misery
+            [33198] = (IsWotlk and -1 or nil), -- Misery
+        },
+        [126] = {
+            [47000] = (IsWotlk and 15 or 13), -- Improved Blink
+            [31965] = -3, -- Spell Debuffs 2 (80)
+            [46989] = (IsWotlk and 30 or 25), -- Improved Blink
+            [455868] = -1, -- Revealed Weakness
+            [31224] = 90, -- Cloak of Shadows
+            [39666] = 90, -- Cloak of Shadows
+            [462873] = 90, -- Cloak of Shadows
+            [65961] = 90, -- Cloak of Shadows
+            [50240] = 200, -- Evasive Maneuvers
+        },
+    },
     IsFeralForm = {
         [768] = true, -- Cat Form
         [5487] = true, -- Bear Form
@@ -786,6 +848,30 @@ Data.Item = {
         [234032] = 2,
     },
 }
+Data.Talent = {
+    [Data.MAGE] = {
+        ARCTIC_WINDS = {31674,31675,31676,31677,31678}
+    },
+    [Data.DEATHKNIGHT] = {
+        FRIGID_DREADPLATE = {49186,51108,51109},
+    },
+    [Data.HUNTER] = {
+        DISPLACEMENT = {34478,34479,34481},
+    },
+    [Data.ROGUE] = {
+        HEIGHTENED_SENSES = {30894,30895},
+    },
+    [Data.PALADIN] = {
+        PURSUIT_OF_JUSTICE = {26022,26023,44414},
+        DIVINE_PURPOSE = {31871,31872},
+    },
+    [Data.PALADIN] = {
+        BALANCE_OF_POWER = {33592,33596},
+    },
+    [Data.WARRIOR] = {
+        IMPROVED_SPELL_REFLECTION = {59088,59089},
+    },
+}
 Data.setNames = {
     AUGURS_REGALIA = "Augur's Regalia",
     BLOODSOUL_EMBRACE = "Bloodsoul Embrace",
diff --git a/Modules/Data/Defense.lua b/Modules/Data/Defense.lua
index f9511d57..fa5eaa3f 100755
--- a/Modules/Data/Defense.lua
+++ b/Modules/Data/Defense.lua
@@ -1,3 +1,11 @@
+local IsTBC = ECS.IsTBC
+local IsWotlk = ECS.IsWotlk
+local IsSpellKnown = C_SpellBook.IsSpellKnown
+local GetDebuffDataByIndex = C_UnitAuras.GetDebuffDataByIndex
+local GetBuffDataByIndex = C_UnitAuras.GetBuffDataByIndex
+local band = bit.band
+local pairs = pairs
+
 ---@class Data
 local Data = ECSLoader:ImportModule("Data")
 ---@type DataUtils
@@ -8,7 +16,18 @@ local Utils = ECSLoader:ImportModule("Utils")
 local _Defense = {}
 
 local _, _, classId = UnitClass("player")
-
+local DRUID = Data.DRUID
+local DEATHKNIGHT = Data.DEATHKNIGHT
+local WARRIOR = Data.WARRIOR
+local MAGE = Data.MAGE
+local PALADIN = Data.PALADIN
+local HUNTER = Data.HUNTER
+local ROGUE = Data.ROGUE
+local Talent = Data.Talent
+local FROST = Data.FROST_SCHOOL
+local NATURE = Data.NATURE_SCHOOL
+local ARCANE = Data.ARCANE_SCHOOL
+local SHADOW = Data.SHADOW_SCHOOL
 local MAX_SKILL = (UnitLevel("player")) * 5
 -- Every 25 defense reduce the chance to be critically hit by 1 %
 local DEFENSE_FOR_CRIT_REDUCTION = 25
@@ -236,3 +255,120 @@ function _Defense:GetEnchantsBlockValue()
     end
     return mod
 end
+
+---@return table<number>
+function _Defense:GetHitReduction()
+    local hitReduction = {
+        spell = {0,0,0,0,0,0,0},
+        melee= 0,
+        ranged = 0
+    }
+
+    local i = 1
+    repeat
+        local aura = GetBuffDataByIndex("player", i)
+        i = i + 1
+        if aura and aura.spellId then
+            hitReduction.melee = hitReduction.melee + (Data.Aura.HitReductionMelee[aura.spellId] or 0)
+            hitReduction.ranged = hitReduction.ranged + (Data.Aura.HitReductionRanged[aura.spellId] or 0)
+
+            for k,v in pairs(Data.Aura.HitReductionSpell) do
+                for s=1,7 do
+                    if ((k == 0) or band(k,s-1) ~= 0x0) then
+                        hitReduction.spell[s] = hitReduction.spell[s] + (v[aura.spellId] or 0)
+                    end
+                end
+            end
+        end
+    until (not aura)
+    i = 1
+    repeat
+        local aura = GetDebuffDataByIndex("player", i)
+        i = i + 1
+        if aura and aura.spellId then
+            hitReduction.melee = hitReduction.melee + (Data.Aura.HitReductionMelee[aura.spellId] or 0)
+            hitReduction.ranged = hitReduction.ranged + (Data.Aura.HitReductionRanged[aura.spellId] or 0)
+
+            for k,v in pairs(Data.Aura.HitReductionSpell) do
+                for s=1,7 do
+                    if ((k == 0) or band(k,s-1) ~= 0x0) then
+                        hitReduction.spell[s] = hitReduction.spell[s] + (v[aura.spellId] or 0)
+                    end
+                end
+            end
+        end
+    until (not aura)
+
+    if IsWotlk then
+        if IsSpellKnown(20582) then -- Quickness
+            hitReduction.melee = hitReduction.melee + 2
+            hitReduction.ranged = hitReduction.ranged + 2
+        end
+        if IsSpellKnown(822) then -- Magic Resistance
+            for s=1,7 do
+                if band(126,s-1) ~= 0x0 then
+                    hitReduction.spell[s] = hitReduction.spell[s] + 2
+                end
+            end
+        end
+        if IsSpellKnown(20579) then -- Magic Resistance
+            for s=1,7 do
+                if band(126,s-1) ~= 0x0 then
+                    hitReduction.spell[s] = hitReduction.spell[s] + 2
+                end
+            end
+        end
+        hitReduction.spell[ARCANE] = hitReduction.spell[ARCANE] + (IsSpellKnown(20592) and 2 or 0) -- Arcane Resistance
+        hitReduction.spell[FROST] = hitReduction.spell[FROST] + (IsSpellKnown(20596) and 2 or 0) -- Frost Resistance
+        hitReduction.spell[NATURE] = hitReduction.spell[NATURE] + (IsSpellKnown(20583) and 2 or 0) -- Nature Resistance
+        hitReduction.spell[NATURE] = hitReduction.spell[NATURE] + (IsSpellKnown(20551) and 2 or 0) -- Nature Resistance
+        hitReduction.spell[SHADOW] = hitReduction.spell[SHADOW] + (IsSpellKnown(59535) and 2 or 0) -- Shadow Resistance
+        hitReduction.spell[SHADOW] = hitReduction.spell[SHADOW] + (IsSpellKnown(59540) and 2 or 0) -- Shadow Resistance
+        hitReduction.spell[SHADOW] = hitReduction.spell[SHADOW] + (IsSpellKnown(59538) and 2 or 0) -- Shadow Resistance
+        hitReduction.spell[SHADOW] = hitReduction.spell[SHADOW] + (IsSpellKnown(59221) and 2 or 0) -- Shadow Resistance
+        hitReduction.spell[SHADOW] = hitReduction.spell[SHADOW] + (IsSpellKnown(59541) and 2 or 0) -- Shadow Resistance
+        hitReduction.spell[SHADOW] = hitReduction.spell[SHADOW] + (IsSpellKnown(59536) and 2 or 0) -- Shadow Resistance
+    end
+
+    local spellMod = 0
+    if classId == DRUID then
+        spellMod = 3 * DataUtils:GetActiveTalentSpell(Talent[DRUID].BALANCE_OF_POWER) -- 126
+    elseif classId == ROGUE then
+        local mod = 2 * DataUtils:GetActiveTalentSpell(Talent[ROGUE].HEIGHTENED_SENSES)
+        spellMod = mod -- 126
+        hitReduction.ranged = hitReduction.ranged + mod
+    elseif classId == PALADIN then
+        if IsTBC then
+            spellMod = 1 * DataUtils:GetActiveTalentSpell(Talent[PALADIN].PURSUIT_OF_JUSTICE) -- 126
+        elseif IsWotlk then
+            local mod = 2 * DataUtils:GetActiveTalentSpell(Talent[PALADIN].DIVINE_PURPOSE)
+            spellMod = mod -- 126
+            hitReduction.ranged = hitReduction.ranged + mod -- 127
+        end
+    elseif classId == DEATHKNIGHT then
+        hitReduction.melee = hitReduction.melee + 1 * DataUtils:GetActiveTalentSpell(Talent[DEATHKNIGHT].FRIGID_DREADPLATE)
+    elseif classId == HUNTER then
+        if not ECS.IsClassic then
+            local mod = 1 * DataUtils:GetActiveTalentSpell(Talent[HUNTER].DISPLACEMENT)
+            spellMod = mod -- 126
+            hitReduction.ranged = hitReduction.ranged + mod
+            hitReduction.melee = hitReduction.melee + mod
+        end
+    elseif classId == MAGE then
+        if not ECS.IsClassic then
+            local mod = 1 * DataUtils:GetActiveTalentSpell(Talent[MAGE].ARCTIC_WINDS)
+            hitReduction.ranged = hitReduction.ranged + mod
+            hitReduction.melee = hitReduction.melee + mod
+        end
+    elseif classId == WARRIOR then
+        spellMod = 2 * DataUtils:GetActiveTalentSpell(Talent[WARRIOR].IMPROVED_SPELL_REFLECTION) -- 126
+    end
+
+    for s=1,7 do
+        if band(126,s-1) ~= 0x0 then
+            hitReduction.spell[s] = hitReduction.spell[s] + spellMod
+        end
+    end
+
+    return hitReduction
+end
diff --git a/types/types.lua b/types/types.lua
index 48e5fe55..d4c96a14 100644
--- a/types/types.lua
+++ b/types/types.lua
@@ -27,3 +27,4 @@
 ---@alias EquipSlot string
 ---@alias ItemLink string
 ---@alias Color string
+---@alias Bitmask number
\ No newline at end of file