Specialization

Specialization refers to choosing a primary talent tree. A character is asked choose a specialization at level 10 before spending their first talent point. Making that choice gives the character some passive bonuses they need in order to be effective in their chosen role, as well as a signature ability – known as a primary ability – of their tree.

Each tree has it's own Mastery. You may learn Mastery from your trainer at level 80. Each point of Mastery skill (not rating) obtained from gear and other sources will further increase the bonus.

For hybrid classes, selecting a specialization will determine the role (healing, tanking, melee DPS or ranged DPS) that the character is optimized for.

For hybrid classes (excluding Priests) a character's specialization will also determine the attribute increased by the armor specialization bonus. The armor specialization bonus is a 5% increase of your primary attribute while wearing your correct armor class (plate, mail, leather or cloth) in all slots. For hybrids, the primary attribute depends on the specialization chosen.

Intellect is considered the primary attribute for healers and offensive casters, i.e. all Mages, all Warlocks, all Priests, Balance and Restoration Druids, Elemental and Restoration Shaman and Holy Paladins.

Agility is considered the primary attribute for leather and mail wearing melee damage dealers and hunters, i.e. Feral Druids in cat form, all Rogues, all Hunters and Enhancement Shaman.

Strength is considered the primary attribute for plate wearing melee damage dealers, i.e. Arms and Fury Warriors, Frost and Unholy Death knights and Retribution Paladins.

Stamina is considered the primary attribute for tanks i.e. Feral Druids in bear form, Blood Death knights, Protection Warriors and Protection Paladins.

To sum up, selecting a Specialization will determine:
 * Role i.e Tanking, Healing, Ranged DPS or Melee DPS (hybrid classes only)
 * Primary attribute buffed by armor specialization (hybrid classes only)
 * Primary ability
 * Passive bonuses
 * Mastery

Note that for the pure classes (Hunters, Mages, Rogues and Warlocks), the character's role and primary attribute are independant of Specialization selected. In addition the primary attribute of a Priest is independant of Specialization inspite of the fact that Priests are a hybrid class (because both of their roles benefit from Intellect).

Class Specializations
Note: The abilities and passive bonuses listed below are obtained just for selecting a talent tree and do not cost a single talent point, though they do not activate until a tree is selected and the first point is placed. Damage and Healing numbers given for abilities reflect maximum rank (Level 85)

Death knight
Blood: A dark guardian who manipulates and corrupts life energy to sustain self in the face of an enemy onslaught.
 * Role
 * Tanking
 * Primary Spell
 * Heart Strike: Instantly strike the target and up to two additional nearby enemies, causing 175% weapon damage plus 819 on the primary target, with each additional enemy struck taking 25% less damage than the previous target. Damage dealt to each target is increased by an additional 15% for each of your diseases present.
 * Passive Bonuses
 * Veteran of the Third War: Increases your total Stamina by 9% and your expertise by 6.
 * Blood Rites: Whenever you hit with Death Strike or Obliterate, the Frost and Unholy Runes will become Death Runes when they activate. Death Runes count as a Blood, Frost or Unholy Rune.
 * Vengeance: Each time you take damage, you gain 5% of the damage taken as attack power, up to a maximum of 10% of your health.
 * Mastery
 * Blood Shield: Each time you heal yourself with Death Strike while in Blood Presence, you gain 50% of the amount healed as a damage absorption shield. Each point of Mastery increases the shield by an additional 6.25%.

Frost: An icy harbinger of doom, channeling runic power and delivering rapid weapon strikes.
 * Role
 * Melee DPS
 * Primary Spell
 * Frost Strike: Instantly strike the enemy, causing 130% weapon damage plus 277 as Frost damage.
 * Passive Bonuses
 * Icy Talons: Your melee attack speed is increased by 20%
 * Blood of the North: Permanently transforms your Blood Runes into Death Runes. Death Runes count as a Blood, Frost, or Unholy Rune.
 * Mastery
 * Frozen Heart: Increases all frost damage done by 16%. Each point of Mastery increases frost damage by an additional 2.0%.

Unholy: A master of death and decay, spreading infection and controlling undead minions to do  bidding.
 * Role
 * Melee DPS
 * Primary Spell
 * Scourge Strike: An unholy strike that deals 100% of weapon damage as Physical damage plus 624. In addition, for each of your diseases on your target, you deal an additional 18% of the Physical damage done as Shadow damage.
 * Passive Bonuses
 * Master of Ghouls: Reduces the cooldown on Raise Dead by 60 sec, and the Ghoul summoned by your Raise Dead spell is considered a pet under your control. Unlike normal Death Knight Ghouls, your pet does not have a limited duration.
 * Reaping: Whenever you hit with Blood Strike, Pestilence, or Festering Strike, the Runes spent will become Death Runes when they activate. Death Runes count as a Blood, Frost or Unholy Rune.
 * Unholy Might: Dark power courses through your limbs, increasing your Strength by 20%.
 * Mastery
 * Dreadblade: Increases Shadow damage done by 20%. Each point of Mastery increases Shadow damage by an additional 2.5%.

Druid
Balance: Can take on the form of a powerful Moonkin, balancing the power of Arcane and Nature magic to destroy enemies at a distance. Increases the critical strike damage bonus of your Wrath, Moonfire, Starfire, Insect Swarm and Starfall spells by 100%.
 * Role
 * Ranged Magical DPS
 * Primary Spell
 * Starsurge: You fuse the power of the moon and sun, launching a devastating blast of energy at the target. Causes 1018 to 1404 Spellstorm damage to the target and generates 15 Lunar or Solar energy, whichever is more beneficial to you.
 * Passive Bonuses
 * Moonfury: Arcane and Nature spell damage increased by 10%.
 * Mastery
 * Total Eclipse: Increases the bonus damage from Eclipse by 16%. Each point of Mastery increases the bonus by an additional 3%.

Feral Combat: Takes on the form of a great cat to deal damage with bleeds and bites or a mighty bear to absorb damage and protect allies.
 * Role
 * Tanking (In Bear Form)
 * Melee DPS (In Cat Form)
 * Primary Spell
 * Mangle: Mangle the target, inflicting damage and causing the target to take additional damage from bleed effects for 1 min. This ability can be used in Cat Form or Bear Form.
 * Passive Bonuses
 * Aggression (druid talent): Increases your attack power by 25%.
 * Vengeance: Requires Bear Form. Each time you take damage while in Bear Form, you gain 5% of the damage taken as attack power, up to a maximum of 10% of your health. Entering Cat form will cancel this effect.
 * Feral Instinct: Reduces the chance enemies have to detect you while Prowling.
 * Mastery
 * Savage Defender (Requires Bear Form): Increases the damage absorbed by your Savage Defense ability by 32%. Each point of Mastery increases the absorb by an additional 4%.
 * Razor Claws (Requires Cat Form): Increases the damage done by your bleed abilities by 25.04%. Each point of Mastery increases bleed damage by an additional 3.1%.

Restoration: Uses heal-over-time Nature spells to keep allies alive, taking on the form of a tree when the need is most urgent.
 * Role
 * Healing
 * Primary Spell
 * Swiftmend: Consumes a Rejuvenation or Regrowth effect on a friendly target to instantly heal the target for 5229.
 * Passive Bonuses
 * Meditation: Allows 50% of your mana regeneration from Spirit to continue while in combat.
 * Gift of Nature: Healing increased by 25%.
 * Disentanglement: The Druid to clear all roots when Shapeshifting in addition to snares.
 * Mastery
 * Harmony:Your direct healing is increased by an additional 10% and casting your direct healing spells grants you an additional 10% bonus to periodic healing for 10 sec. Each point of Mastery increases each bonus by an additional 1.25%.

Hunter
Beast Mastery: A master of the wild who can tame a wide variety of beasts to assist  in combat.
 * Role
 * Ranged Physical DPS
 * Primary Spell
 * Intimidation: Command your pet to intimidate the target, causing a high amount of threat and stunning the target for 3 sec. Lasts 15 sec.
 * Passive Bonuses
 * Animal Handler: Attack Power increased by 25%.
 * Mastery
 * Master of Beasts: Increases the damage done by your pets by 13.6%. Each point of Mastery increases pet damage by an additional 1.7%.

Marksmanship: A master archer or sharpshooter who excels in bringing down enemies from afar.
 * Role
 * Ranged Physical DPS
 * Primary Spell
 * Aimed Shot: A powerful aimed shot that deals 160% ranged weapon damage plus (RAP * 0.724)+776.
 * Passive Bonuses
 * Artisan Quiver: Ranged auto-attack damage increased by 15%.
 * Mastery
 * Wild Quiver: Grants a 14.4% chance for your ranged attacks to also instantly fire an additional ranged shot for 50% normal damage. Each point of Mastery increases the chance by an additional 1.8%.

Survival: A rugged tracker who favors using animal venom, explosives and traps as deadly weapons.
 * Role
 * Ranged Physical DPS
 * Primary Spell
 * Explosive Shot: You fire an explosive charge into the enemy target, dealing RAP*0.273+453 Fire damage. The charge will blast the target every second for an additional 2 sec.
 * Passive Bonuses
 * Into the Wilderness: Agility increased by 15%.
 * Mastery
 * Essence of the Viper: Increases all elemental damage you deal by 8%. Each point of Mastery increases pet damage by an additional 1%.

Mage
Arcane: Manipulates arcane energies, playing with the very fabric of time and space.
 * Role
 * Ranged Magical DPS
 * Primary Spell
 * Arcane Barrage: Launches bolts of arcane energy at the enemy target, causing 1044 to 1274 Arcane damage.
 * Passive Bonuses
 * Arcane Specialization: Increases the damage of your Arcane spells by 25%.
 * Mastery
 * Mana Adept: Increases all spell damage done by up to 12%, based on the amount of mana the Mage has unspent. Each point of Mastery increases damage done by up to an additional 1.5%.

Fire: Ignites enemies with balls of fire and the breath of dragons.
 * Role
 * Ranged Magical DPS
 * Primary Spell
 * Pyroblast: Hurls an immense fiery boulder that causes 1291 to 1639 Fire damage and an additional 872 Fire damage over 12 sec.
 * Passive Bonuses
 * Fire Specialization: Increases the damage of your Fire spells by 25%.
 * Mastery
 * Flashburn: Increases the damage done by all your periodic fire damage effects by 22.4%. Each point of Mastery increases periodic damage done by an additional 2.8%.

Frost: Freezes enemies in their tracks and shatters them with Frost magic.
 * Role
 * Ranged Magical DPS
 * Primary Spell
 * Summon Water Elemental: Summon a Water Elemental to fight for the caster.
 * Passive Bonuses
 * Frost Specialization: Increases the damage of your Frost spells by 25% and of your Frostbolt spell by an additional 15%.
 * Mastery
 * Frostburn: All your spells deal 5% increased damage against Frozen targets. Each point of Mastery increases damage by an additional 2.5%.

Paladin
Holy: Invokes the power of the Light to protect and to heal.
 * Role
 * Healing
 * Primary Spell
 * Holy Shock: Blasts the target with Holy energy, causing 1399 to 1515 Holy damage to an enemy, or 2629 to 2847 healing to an ally, and grants a charge of Holy Power.
 * Passive Bonuses
 * Walk in the Light: Increases the effectiveness of your healing spells by 10% and removes the cooldown on your Word of Glory.
 * Meditation: Allows 50% of your mana regeneration from Spirit to continue while in combat.
 * Mastery
 * Illuminated Healing: Your direct healing spells also place an absorb shield on your target for 12% of the amount healed lasting 15 sec. Each point of Mastery increases the absorb amount by an additional 1.50%.

Protection: Uses Holy magic to shield  and defend allies from attackers.
 * Role
 * Tanking
 * Primary Spell
 * Avenger's Shield: Hurls a holy shield at the enemy, dealing 2802 to 3424 Holy damage, silencing them, interrupting for 3 sec, and then jumping to additional nearby enemies. Affects 3 total targets.
 * Passive Bonuses
 * Vengeance: Each time you take damage, you gain 5% of the damage taken as attack power, up to a maximum of 10% of your health.
 * Touched by the Light: Increases your total Stamina by 15%, increases your spell hit by 8%, and increases your spell power by an amount equal to 60% of your Strength.
 * Judgements of the Wise: Your Judgement grants you 30% of your base mana over 10 sec.
 * Mastery
 * Divine Bulwark: Increases your chance to block melee attacks by 18%. Each point of Mastery increases block chance by an additional 2.25%.

Retribution: A righteous crusader who judges and punishes opponents with weapons and Holy magic. 1 Holy Power: 30% Weapon Damage
 * Role
 * Melee DPS
 * Primary Spell
 * Templar's Verdict: An instant weapon attack that causes a percentage of weapon damage. Consumes all charges of Holy Power to increase damage dealt:

2 Holy Power: 90% Weapon Damage

3 Holy Power: 235% Weapon Damage
 * Passive Bonuses
 * Sheath of Light: Increases your spell power by an amount equal to 30% of your attack power and increases your chance to hit with spells by 8%.
 * Two-Handed Weapon Specialization (paladin specialization): Increases the damage you deal with two-handed melee weapons by 20%.
 * Judgements of the Bold: Your Judgement grants you 25% of your base mana over 10 sec.
 * Mastery
 * Hand of Light: Your Templar's Verdict, Crusader Strike, and Divine Storm deal 16.8% additional damage as Holy damage. Each point of Mastery increases the damage by an additional 2.1%.

Priest
Discipline: Uses magic to shield allies from taking damage as well as heal their wounds.
 * Role
 * Healing
 * Primary Spell
 * Penance: Launches a volley of holy light at the target, causing 699 to 789 Holy damage to an enemy, or 2352 to 2656 healing to an ally instantly and every 1 sec for 2 sec.
 * Passive Bonuses
 * Enlightenment: Intellect increased by 15%.
 * Meditation: Allows 50% of your mana regeneration from Spirit to continue while in combat.
 * Absolution: Enables your Dispel Magic spell to be cast on friendly targets to remove 2 harmful magical effects.
 * Mastery
 * Shield Discipline: Increases the potency of all your damage absorption spells by 20%.  Each point of Mastery increases the potency of absorbs by an additional 2.5%.

Holy: A versatile healer who can reverse damage on individuals or groups and even heal from beyond the grave.
 * Role
 * Healing
 * Primary Spell
 * Holy Word: Chastise: Chastise the target for 564 to 632 Holy damage, and disorients them for 3 sec.
 * Passive Bonuses
 * Spiritual Healing: Healing increased by 15%.
 * Meditation: Allows 50% of your mana regeneration from Spirit to continue while in combat.
 * Absolution: Enables your Dispel Magic spell to be cast on friendly targets to remove 2 harmful magical effects.
 * Mastery
 * Echo of Light: Your direct healing spells heal for an additional 10% over 6 sec. Each point of Mastery provides an additional 1.25% healing over 6 sec.

Shadow: Uses sinister Shadow magic, especially damage-over-time spells, to eradicate enemies.
 * Role
 * Ranged Magical DPS
 * Primary Spell
 * Mind Flay: Assault the target's mind with Shadow energy, causing 501 Shadow damage over 3 sec and slowing their movement speed by 50%.
 * Passive Bonuses
 * Shadow Power: Spell damage increased by 15%. Increases the critical damage of your Shadow spells by 100%.
 * Shadow Orbs:You have a 10% chance for your Shadow Word: Pain and Mind Flay spells to grant you a Shadow Orb each time they deal damage. Casting your Mind Blast or Mind Spike spell consumes all Shadow Orbs, increasing damage of that spell by 10% per Shadow Orb, and granting 10% increased damage on your periodic Shadow spells for 15 sec.  You can have up to a maximum of 3 orbs.
 * Mastery
 * Shadow Orb Power: Increases the damage done by your Shadow Orbs by 11.6%. Each point of Mastery increases damage by an additional 1.45%.

Rogue
Assassination: A deadly master of poisons who dispatches victims with vicious dagger strikes.
 * Role
 * Melee DPS
 * Primary Spell
 * Mutilate: Instantly attacks with both weapons for 150% weapon damage plus an additional 201 with each weapon. Damage is increased by 20% against Poisoned targets.  Awards 2 combo points.
 * Passive Bonuses
 * Improved Poisons: Increases the chance to apply Deadly Poison to your target by 20% and the frequency of applying Instant Poison to your target by 50%.
 * Assassin's Resolve: While wielding daggers, your maximum Energy is increased by 20 and your melee damage is increased by 15%.
 * Mastery
 * Potent Poisons: Increases the damage done by your poisons by 28%. Each point of Mastery increases damage by an additional 3.5%.

Combat: A swashbuckler who uses agility and guile to stand toe-to-toe with enemies.
 * Role
 * Melee DPS
 * Primary Spell
 * Blade Flurry: While active, the rogue's attacks strike an additional nearby opponent, but energy regeneration is reduced by 30%. Lasts until cancelled.
 * Passive Bonuses
 * Vitality (rogue talent): Increases your Energy regeneration rate by 25% and your Attack Power by 25%.
 * Ambidexterity: Increases the damage done by your off hand and thrown weapons by 75%.
 * Mastery
 * Main Gauche: Your main hand attacks have a 16% chance to grant you an attack that deals damage equal to 100% of a main hand attack. Each point of Mastery increases the chance by an additional 2.00%.

Subtlety: A dark stalker who leaps from the shadows to ambush  unsuspecting prey.
 * Role
 * Melee DPS
 * Primary Spell
 * Shadowstep: Causes you to step through the shadows and appear behind an enemy target. Your next Ambush or Garrote delivered within 10 sec will deal 30% additional damage, and your movement speed is increased by 70% for 3 sec.
 * Passive Bonuses
 * Master of Subtlety: Attacks made while stealthed and for 6 seconds after breaking stealth cause an additional 10% damage.
 * Sinister Calling: Increases your total Agility by 25% and increases the percentage damage bonus of Backstab and Hemorrhage by an additional 25%.
 * Mastery
 * Executioner: Increases the damage done by all your finishing moves, and the effectiveness of your Slice and Dice, by 20%. Each point of Mastery increases damage by an additional 2.5%.

Shaman
Elemental: A spellcaster who harnesses the destructive forces of nature and the elements.
 * Role
 * Ranged Magical DPS
 * Primary Spell
 * Thunderstorm: You call down a bolt of lightning, energizing you and damaging nearby enemies within 10 yards. Restores 8% mana to you and deals 1529 to 1745 Nature damage to all nearby enemies, knocking them back 20 yards. This spell is usable while stunned.
 * Passive Bonuses
 * Elemental Fury: Increases the critical strike damage bonus of your Searing and Magma Totems and your Fire, Frost, and Nature spells by 100%.
 * Shamanism (shaman talent): Your Lightning Bolt, Chain Lightning, and Lava Burst spells gain an additional 20% benefit from your spell power, and their casting time is reduced by 0.5 sec.
 * Mastery
 * Elemental Overload: Grants a 16% chance for Elemental Overload to occur. Elemental Overload causes a Lightning Bolt, Chain Lightning, or Lava Burst spell you cast to trigger a second, similar spell on the same target at no additional cost that causes 75% of normal damage and no threat.  Each point of Mastery increases the chance of Elemental Overload by an additional 2%.

Enhancement: A totemic warrior who strikes foes with weapons imbued with elemental power.
 * Role
 * Melee DPS
 * Primary Spell
 * Lava Lash: You charge your off-hand weapon with lava, instantly dealing 200% of that weapon's damage to an enemy target. Damage is increased by 40% if your off-hand weapon is enchanted with Flametongue.
 * Passive Bonuses
 * Mental Quickness: Increases your spell power by an amount equal to 50% of your attack power, and reduces the mana cost of your instant spells by 75%.
 * Dual Wield (shaman talent): Allows one-hand and off-hand weapons to be equipped in your off-hand, allows you to parry frontal melee attacks, and increases your chance to hit by an additional 6%.
 * Primal Wisdom Your melee attacks have a 40% chance to immediately restore 5% of your base mana.
 * Mastery
 * Enhanced Elements: Increases all Fire, Frost, and Nature damage done by 20%. Each point of Mastery increases damage by an additional 2.5%

Restoration: A healer who calls upon ancestral spirits and the cleansing power of water to mend allies' wounds.
 * Role
 * Healing
 * Primary Spell
 * Earth Shield: Protects the target with an earthen shield, reducing casting or channeling time lost when damaged by 30% and causing attacks to heal the shielded target for 1770.  This effect can only occur once every few seconds.  9 charges.  Lasts 10 min.  Earth Shield can only be placed on one target at a time and only one Elemental Shield can be active on a target at a time.
 * Passive Bonuses
 * Purification: Increases the effectiveness of your healing spells by 10%, and reduces the casting time of your Healing Wave and Greater Healing Wave spells by 0.5 sec.
 * Meditation: Allows 50% of your mana regeneration from Spirit to continue while in combat.
 * Mastery
 * Deep Healing: Increases the potency of your healing spells by up to 24%, based on the current health level of your target (lower health targets are healed for more). Each point of Mastery increases healing by up to an additional 3.0%.

Warlock
Affliction: A master of Shadow magic who specializes in fear, drains and damage-over-time spells.
 * Role
 * Ranged Magical DPS
 * Primary Spell
 * Unstable Affliction: Shadow energy slowly destroys the target, causing 1115 damage over 15 sec. In addition, if the Unstable Affliction is dispelled it will cause 2007 damage to the dispeller and silence them for 4 sec.  Only one Unstable Affliction or Immolate per Warlock can be active on any one target.
 * Passive Bonuses
 * Shadow Mastery: Increases Shadow spell damage by 30%.
 * Mastery
 * Potent Afflictions: Increases all periodic shadow damage you deal by 13.04%. Each point of Mastery increases periodic shadow damage by an additional 1.63%.

Demonology: A warlock who uses both Fire and Shadow magic along with powerful demons.
 * Role
 * Ranged Magical DPS
 * Primary Spell
 * Summon Felguard: Summons a Felguard under the command of the Warlock.
 * Passive Bonuses
 * Demonic Knowledge: Increases your Fire and Shadow spell damage by 15%.
 * Mastery
 * Master Demonologist: Increases the damage done by your demon servants and damage you deal while transformed into a demon by 16%. Each point of Mastery increases damage by an additional 2.0%.

Destruction: Calls down demonic fire to burn and demolish enemies.
 * Role
 * Ranged Magical DPS
 * Primary Spell
 * Conflagrate: Instantly deals fire damage equal to 60% of your Immolate's periodic damage on the target.
 * Passive Bonuses
 * Cataclysm (warlock talent): Increases Fire spell damage by 25%.
 * Mastery
 * Fiery Apocalypse: Increases all fire damage you deal by 10.8%. Each point of Mastery increases fire damage by an additional 1.35%.

Warrior
Arms: A battle-hardened master of two-handed weapons, using mobility and overpowering attacks to strike  opponents down.
 * Role
 * Melee DPS
 * Primary Spell
 * Mortal Strike: A vicious strike that deals 150% weapon damage plus 423 and wounds the target, reducing the effectiveness of any healing received by 10% for 10 sec.
 * Passive Bonuses
 * Anger Management: You generate 1 rage every 3 seconds and 25% extra rage from damage dealt.
 * Two-Handed Weapon Specialization (warrior specialization): Increases the damage you deal with two-handed melee weapons by 12%.
 * Mastery
 * Strikes of Opportunity: Grants a 17.6% chance for your melee attacks to instantly trigger an additional melee attack for 100% normal damage. Each point of Mastery increases this chance by 2.2%.

Fury: A furious berserker wielding a weapon in each hand, unleashing a flurry of attacks to carve  opponents to pieces.
 * Role
 * Melee DPS
 * Primary Spell
 * Bloodthirst: Instantly attack the target causing (AP * 80 / 100) damage. In addition, the next 3 successful melee attacks will restore 0.5% of max health.  This effect lasts 8 sec.  Damage is based on your attack power.
 * Passive Bonuses
 * Dual Wield Specialization: Allows you to equip one-hand and off-hand weapons in your off-hand. Increases all Physical damage by 5% and raises the damage of your off-hand attacks by an additional 25%.
 * Precision (warrior talent): Increases your chance to hit with your attacks by 3% and increases auto attack damage by 40%.
 * Mastery
 * Unshackled Fury: Increases the benefit of abilities that cause or require you to be enraged by 11.2%. Each point of Mastery increases enrage effects by an additional 5.60%.

Protection: A stalwart protector who uses a shield to safeguard  and  allies.
 * Role
 * Tanking
 * Primary Spell
 * Shield Slam: Slam the target with your shield, causing 1872 to 1966 damage (based on attack power) and dispelling 1 magic effect on the target. Also causes a high amount of threat.
 * Passive Bonuses
 * Sentinel (warrior talent): Increases your total Stamina by 15% and your block chance by 15%. You also generate 50% additional rage from attacking targets that are not targeting you.
 * Vengeance: Each time you take damage, you gain 5% of the damage taken as attack power, up to a maximum of 10% of your health.
 * Mastery
 * Critical Block: Increases your chance to block by 12% and your chance to critically block by 12%. Each point of Mastery increases your block and critical block chances by an additional 1.5%.