Spell Power

Spell Power (also Ability power) modification increases or decreases the Spell Damage, Healing done by a Hero's Abilities. Summoned creatures (Zagara Roaches, Azmodan Demons, etc.) deal ability damage which can be enhanced by the Hero’s Spell Power in real-time. Shields are not affected by Spell Power, but healing done to Shields, through talents like Fenix's "Rapid Recharge", however is.

A Spell Power value greater than 0% effectively increases the damage dealt or healing provided by the same percentage (ex: An ability that deals 100 damage would deal 140 damage with 40% Spell Power, 100*(100%+40%) = 140). Similarly, a Spell Power value less than 0% effectively decreases the damage dealt or healing provided by that percentage (ex: An ability that deals 100 damage would deal 60 damage with -40% Spell Power, 100*(100%-40%) = 60). Damage modified by Spell Power is calculated the moment the target is hit.

Spell Power modification is calculated after Scaling and flat damage bonuses from Talents.

Spell Power does not affect Healing gained through Lifesteal, though can alter lifesteal amount based on spell damage by altering this damage.

Abilities and Talents that affect self Spell Power

 * Chromie's level 1 talent, "Timewalker's Pursuit", grants her 15% increased Spell Power.
 * Chromie's level 14 talent, "Shifting Sands", adds an additional effect to her "Sand Blast" ability, granting her 5% increased Spell Power for 8 seconds for Hero hit, stacking up to 50%.
 * Chromie's level 14 talent, "Quantum Overdrive", grants her 30% increased Spell Power for 8 seconds.
 * Deckard's level 1 talent "Field Study", grants him 20% Spell Power for 14 seconds for each Hero hit by "Scroll of Sealing", stacking up to 30%.
 * Diablo's level 13 talent "Hellfire", grants him 3% Spell Power for each enemy Hero hit by Fire Stomp for 10 seconds, stacking up to 30%.
 * Gazlowe's level 13 talent "Overcharged Capacitors" grant him 5% Spell Power for each active "Rock-It! Turret", stacking up to 15%.
 * Gul'dan's level 7 talent, "Hunger for Power", permanently grants him 15% increased Spell Power, but reduces allied healing.
 * Gul'dan's level 16 talent, "The Darkness Within", adds an additional effect to his "Life Tap" trait, granting him 25% increased Spell Power for 5 seconds after dealing enough damage to Heroes and using Life Tap.
 * Hanzo's level 7 talent, "The Dragon Hungers", adds an additional effect to his "Storm Bow" ability, granting him 5% increased Spell Power for 10 seconds for every Hero hit, stacking up to 20%.
 * Jaina's level 4 talent, "Arcane Intelligence", grants her 10% Spell Power while above 75% maximum Mana.
 * Kael'thas's level 1 talent, "Fel Infusion", permanently grants him 4% increased Spell Power.
 * Kael'thas's level 7 talent, "Sunfire Enchantment", adds an additional effect to his "Verdant Spheres" ability, granting him 15% increased Spell Power for 10 seconds if his next 2 basic attacks hit heroes.
 * Kel'Thuzad's trait, "Master of the Cold Dark", grants him 75% increased Spell Power after he completes the quest.
 * Kel'Thuzad's level 16 talent, "Power of Icecrown", grants him 6% increased Spell Power for 10 seconds for every enemy Hero he stuns, slows or roots, stacking up to 30%.
 * Kerrigan's level 16 talent, "Mounting Potency", adds an additional effect to her "Ravage" ability, granting her 5% Spell Power when she casts it, stacking up to 40% for 5 seconds.
 * Kerrigan's level 16 talent, "Unbridled Energy", grants her 35% increased Spell Power for 4 seconds when she damages an enemy hero with a Heroic Ability.
 * Li Li's level 13 talent, "Surging Winds", adds an additional effect to her "Blinding Winds" ability, granting her 10% increased Spell Power for 10 seconds if the ability hits at least 2 Heroes.
 * Li-Ming's level 1 talent, "Power Hungry", makes Regeneration Globes increase her Spell Power by 10% for 20 seconds.
 * Li-Ming's level 13 talent, "Glass Cannon", permanently grants her 15% increased Spell Power, but reduces her maximum Health.
 * Li-Ming's level 20 talent, "Tal Rasha's Elements", grants her 5% increased Spell Power for every Ability used until the use of the same Ability, stacking up to 20%.
 * Medivh's level 7 talent, "Force of Magic", adds an additional effect to his "Force of Will" ability, granting him 25% increased Spell Power for 15 seconds if it prevents a certain amount of damage, stacking up to 50%.
 * Murky's level 4 talent, "Living the Dream", grants him 5% increased Spell Power for every 15 seconds he remains alive, stacking up to 20%.
 * Nazeebo's level 1 talent, "Thing of the Deep", permanently grants him 5% increased Spell Power upon reaching 50 stacks of "Voodoo Ritual", and an additional permanent 5% Spell Power upon reaching 100 stacks.
 * Nazeebo's level 16 talent, "Soul Harvest", grants him 7% increased Spell Power for every nearby enemy, up to 35%, for 15 seconds.
 * Tassadar's level 16 talent, "Executor's Will", grants him 15% increased Spell Power for as long as he has maximum Resonance.
 * Whitemane's trait, "Zeal", can be activated to grant her 25% increased Spell Power for 5 seconds.
 * Yrel's level 13 talent, "Velen's Chosen", grants her 10% increased Spell Power for 10 seconds if a Hero is hit by a basic ability at maximum charge, stacking up to 30%.
 * Zul'jin's level 1 talent, "Recklessness", grants him 10% increased Spell Power as long as he is below 75% health.

Abilities and Talents that affect allied Spell Power

 * Ana's heroic ability, "Nano Boost", increases target allied Hero's Spell Power by 30% for 8 seconds.
 * Auriel's level 16 talent, "Wrath of Heaven", adds an additional effect to her "Bestow Hope" trait, granting 10% increased Spell Power to the allied Heroes affected by it.
 * Kharazim's level 4 talent, "Air Ally", once placed grants nearby allied Heroes 15% Spell Power for its duration.
 * Medivh's level 20 talent, "Arcane Brilliance", grants nearby allied Heroes 10% increased Spell Power for 10 seconds.
 * Probius' level 13 talent, "Power Overflowing", adds an additional effect to his "Warp In Pylon" trait, granting 10% increased Spell Power to the allied Heroes in his Pylon's Power Field.
 * Tassadar's level 20 talent, "Khala's Gift", grants himself 4% increased Spell Power for each nearby allied hero, up to 20%, shared between all contributing heroes.
 * Varian's level 16 talent, "Banner of Dalaran", grants allied Heroes 20% increased Spell Power in its area of effect for up to 12 seconds.

Abilities and Talents that affect enemy Spell Power

 * Ana's level 7 talent, "Mind-Numbing Agent", adds an additional effect to her "Shrike" trait, reducing enemy Heroes' Spell Power by 10% for every Dose active on them.
 * Anub'arak's level 16 talent, "Debilitation", adds an additional effect to his "Impale" and "Burrow Charge" abilities, reducing the Spell Power of enemy Heroes hit by 50% for 5 seconds.
 * Blaze's level 13 talent, "Suppressive Fire", adds an additional effect to his "Flame Stream" ability, reducing the Spell Power of enemy Heroes hit by 25% for every stream for 4 seconds, stacking up to 50%.
 * Chen's level 4 talent, "Withering Flames", adds an additional effect to his "Breath of Fire" ability, reducing the Spell Power of enemy Heroes hit by 50% for 4 seconds.
 * Garrosh's level 7 talent, "Oppressor", makes his basic attacks reduce target enemy Heroes' Spell Power by 40% for 2.5 seconds.
 * Hogger's level 13 talent, "Pummel", adds an additional effect to his "Hogg Wild" ability, reducing the Spell Power of enemy Heroes hit by it by 50% for 3 seconds.
 * Probius' level 16 talent, "Interference", adds an additional effect to his "Warp Rift" ability, reducing the Spell Power of enemy Heroes hit by its detonation by 35% for 5 seconds.
 * Valeera's level 13 talent, "Strangle", adds an additional effect to her "Garrote" ability, reducing the Spell Power of target enemy Hero by 40% for 6 seconds.