Damage manipulation

“

▶️ That harms me not.

— Abaddon

”

Damage manipulation is a mechanic that alters damage values, either increasing or reducing it. Damage can be manipulated on both ends, from the dealing unit (outgoing damage) and the receiving unit (incoming damage). Armor and magic resistance are the most common damage manipulators, affecting incoming physical and magical damage respectively. Besides armor and magic resistance, a general damage manipulator exists, which is used by almost all other sources of damage manipulation. This manipulator is more flexible, and can amplify or reduce any kind of damage and may affect attack damage, spell damage, or both at the same time.

Generic Damage Manipulator[]

The generic damage manipulator is divided into incoming and outgoing damage manipulation, which results in them stacking multiplicatively. Most abilities that affect damage use the generic damage manipulator.

Incoming Damage[]

Incoming damage manipulation causes the afflicted unit to take increased or reduced damage. All sources within these lists stack additively with each other.

Armor and magic resistance work with incoming damage as well, but are handled separately and not by the generic damage manipulator. This results in them stacking multiplicatively with the general damage manipulator.

Incoming Damage Amplifiers

Ancient Black Drake - Magic Amplification Aura

Damage Amplification: 5%
Aura Linger Duration: 0.5
Aura; Amplifies all spell damage the debuffed enemy takes. Does not amplify attack damage.
Beastmaster - Wild Axes

Damage Amplification per Stack: 6%/8%/10%/12% ( 8.5%/10.5%/12.5%/14.5%)
Duration: 12
Amplifies all damage the debuffed enemy takes from Beastmaster and his units.
Undying - Flesh Golem

Damage Amplification: 25%/30%/35%
Duration: 6
Amplifies all damage the debuffed enemy takes.
Veil of Discord - Magic Weakness

Damage Amplification: 18%
Duration: 16
Amplifies all spell damage the debuffed enemy takes. Does not amplify attack damage.
Hoodwink - Hunter's Boomerang

Damage Amplification: 25%
Duration: 7
Amplifies all spell damage the debuffed enemy takes. Does not amplify attack damage.

Incoming Damage Reducers

Aeon Disk - Combo Breaker

Damage Reduction: 100%
Duration: 2.5
Reduces all damage the hero takes while the effect is active.
Bounty Hunter - Shadow Walk

Damage Reduction: 35%
Duration: 20/25/30/35
Reduces all damage Bounty Hunter takes while invisible.
Bristleback - Bristleback

Rear Damage Reduction: 16%/24%/32%/40%
Side Damage Reduction: 8%/12%/16%/20%
Reduces all damage Bristleback takes from certain angles.
Buildings - Backdoor Protection

Damage Reduction: 50%
Protected Illusion Damage Reduction: 75%
Reduces all damage the building takes while protected, reducing more from illusions.
Centaur Warrunner - Stampede

Damage Reduction: 20%/25%/30%
Duration: 3.5/4/4.5 ( 4.5/5/5.5)
Reduces all damage buffed allies take.
Legion Commander - Duel

Damage Reduction: 50%
Duration: 4/4.75/5.5 ( 6/7/8)
Reduces all damage the duellists take from all sources except each other.
Lich - Frost Shield

Damage Reduction: 30%/40%/50%/60% ( 40%/50%/60%/70%)
Duration: 6 ( 10)
Reduces all hero-based attack damage the buffed unit takes. Does not affect spell damage.
Mars - Bulwark

Front Damage Reduction: 40%/50%/60%/70% ( 50%/60%/70%/80%)
Side Damage Reduction: 20%/25%/30%/35% ( 25%/30%/35%/40%)
Reduces all damage Mars takes from certain angles, using the same targeting rules as damage block. This means it reacts on attacks and on a small selection of abilities.
Nyx Assassin - Burrow

Damage Reduction: 40%
Reduces all damage Nyx Assassin takes while burrowed.
Ogre Magi - Fire Shield

Damage Reduction: 85%
Duration: 25
Applies a buff to a hero that reduces the damage of the next 3 attacks.
Pangolier - Shield Crash

Damage Reduction per hero: 15%/16%/17%/18%
Duration: 5/7/9/11
Reduces all damage Pangolier takes based on the number of stacks.
Spectre - Dispersion

Damage Reduction: 8%/12%/16%/20% ( 13%/17%/21%/25%)
Passively reduces all damage Spectre takes.
Underlord - Fiend's Gate

Ally Damage Reduction: 10%/20%/30%
Duration: 5/6/7
Reduces all damage taken after receiving the buff from using the gate.
Ursa - Enrage

Damage Reduction: 80%
Duration: 4/4.5/5
Reduces all damage Ursa takes while buffed.
Vengeful Spirit - Nether Swap

Ally Damage Reduction: 30%/40%/50%
Duration: 3
Reduces all damage taken by vengeful spirit and the swapped ally.
Visage - Gravekeeper's Cloak

Max Layers: 4
Damage Reduction per Layer: 8%/12%/16%/20%
Damage Reduction Cap: 80%
Layer Recharge Time: 6/5/4/3
Passively reduces all damage Visage takes based on the number of layers. A layer is lost upon taking damage and takes time to recharge.
Winter Wyvern - Winter's Curse

Damage Reduction: 100%
Radius: 525
Duration: 4.5/5/5.5 ( 6/6.5/7)
Reduces all damage the target and all cursed nearby allies take.

Outgoing Damage[]

Outgoing damage manipulation causes the afflicted unit to deal increased or reduced damage. All sources within these lists stack additively with each other.

Spell damage amplification is handled by the general damage manipulator, and not separately. This means all sources of outgoing damage manipulation stack additively with spell damage amplification as well. Outgoing damage manipulators do not apply to damage that is Unaffected by Amplification.

Outgoing Spell Damage Manipulation Sources

Anti-Mage - Counterspell

Outgoing Spell Damage Reduction: 10%
Close Additional Outgoing Spell Damage Reduction: 20%
Aura, passively reduces all spell damage coming from enemies within 900 radius. The close aura applies to enemies within 300 radius. The 2 auras stack additively with themselves.
Bloodseeker - Bloodrage

Outgoing Spell Damage Amplification: 15%/20%/25%/30% ( 23%/28%/33%/38%)
Duration: 8
Applies a buff on the caster or ally hero.
Bloodthorn - Mage Slayer

Outgoing Spell Damage Reduction: 35%
Duration: 6
Reduces all spell damage dealt while affected by the debuff.
Io - Overcharge

Outgoing Spell Damage Amplification: 8%/10%/12%/14% ( 18%/20%/22%/24%)
Duration: 8
Applies a buff on the caster and transfers to the Tethered ally as well.
Mage Slayer - Mage Slayer

Outgoing Spell Damage Reduction: 35%
Duration: 6
Reduces all spell damage dealt while affected by the debuff.
Morphling - Morph

Outgoing Spell Damage Amplification Change: 20%
Grants Morphling bonus outgoing spell damage amplification while reducing the affected target's.
Pugna - Nether Ward

Outgoing Spell Damage Reduction: 10%/15%/20%/25%
Aura, passively reduces all spell damage coming from enemies within 1400 radius.
Rubick - Arcane Supremacy

Outgoing Spell Damage Amplification: 14%/18%/22%/26%
Passively increases Rubick's spell damage.
Rubick - Talent by Level 25 Left
+40% Spell Amp For Stolen Spells:
Only amplifies abilities stolen with Spell Steal.
Shadow Demon - Soul Catcher

Outgoing Spell Damage Amplification Per Dubuff: 5%/7%/9%/11%
Duration: 10
Grants spell amplification based on the number of heroes affected by the spell.

Talents[]

The following heroes have a talent that grants them outgoing spell damage amplification.

Bonus	Level 10		Level 15		Level 20		Level 25
Bonus	Left	Right	Left	Right	Left	Right	Left	Right
Spell Amplification	+6% +6% +8%	+8%		+15% +8%		+10% +11% +12% +18%

Item Sources[]

Many items grant their owners a spell damage amplification bonus by giving them a direct bonus. The effects are limited to the item's owner, which must have the item equipped.

Bonus Spell Damage

Item	Value	Item Cost	Cost/Value Point
Ethereal Blade	12	4650	387.5
Fairy's Trinket	5	N/A	N/A
Kaya	8	2050	256.25
Kaya and Sange	16	4100	256.25
Nether Shawl	6	N/A	N/A
Timeless Relic	15	N/A	N/A
Vambrace (Intelligence)	6	N/A	N/A
Yasha and Kaya	16	4100	256.25
Values may include portions from actives or auras.

Unique Damage Manipulators[]

There are several damage manipulating abilities that do not use the generic damage manipulator. This results in them all stacking multiplicatively with each other and with abilities that do use the generic damage manipulator.

For these abilities, this means if their value is 100%, they are absolute and cannot be altered in any way.

Illusions - Illusion Damage Taken

The increased/reduced damage illusions take is handled separately from all other sources of damage manipulation.
Illusions - Illusion Damage Dealt

The increased/reduced attack damage illusions deal is handled separately from all other sources of damage manipulation. Does not affect their spell damage.
Aeon Disk - Combo Breaker

Outgoing Damage Reduction: 100%
Duration: 2.5
Reduces all damage the hero deals while the effect is active.
Buildings - Backdoor Protection

Illusion Damage Reduction: 60%
Reduces attack damage from illusions.
Kunkka - Ghostship

Incoming Damage Reduction: 40%
Duration: 10
Reduces all damage allies takes while buffed.
Medusa - Mana Shield

Incoming Damage Reduction: 70%
Damage Absorbed per Mana: 1.3/1.7/2.1/2.5
Reduces all damage Medusa takes while active, as long as she has enough mana.
Wraith Pact - Wraith's Reprisal

Outgoing Damage Reduction: 30%
Reduces all damage dealt by heroes within a 900 radius.

Stacking[]

Armor and magic resistance work separately from other damage manipulators. This means they always stack multiplicatively with any other listed ability.

The effects of incoming and outgoing generic damage manipulators stack additively with themselves. Unique damage manipulators stack multiplicatively with themselves. The three sources of damage manipulation stack multiplicatively with each other after they have been combined with all of their own type.

Many source of damage manipulations have conditions on them like Bristleback where it has damage manipulation only on damage that hits his back or sides, so each damage instance calculates damage manipulation separately. Additionally, outgoing generic damage manipulators do not apply to damage that is Unaffected by Amplification.

The total damage manipulation D_M is defined as

D_{M}={\Big (}1+\sum ({\text{Generic Incoming Dmg Manip}}){\Big )}\times {\Big (}1+\sum ({\text{Generic Outgoing Dmg Manip}}){\Big )}\times \prod ({\text{Unique Dmg Manip}})\quad \&\quad D_{M}\geq 0

Stacking outgoing damage manipulation stacks in the same way as incoming damage manipulation, i.e. additively. However, since incoming and outgoing manipulations happen at different times with outgoing manipulation calculation happening first, they stack multiplicatively with each other.

Example 1: Spell Damage Manipulation

Spectre has level 4

Dispersion and is affected by level

Stampede,

Magic Weakness and

Ghostship's rum buff. An enemy casted level 4

Bloodrage on himself and has

Kaya. What would the damage manipulation for Spectre be in this scenario?

Incoming Generic Manipulation sources:

Dispersion: -0.2,

Stampede: -0.3,

Magic Weakness: 0.18.

Outgoing Generic Manipulation sources:

Bloodrage: 0.3,

Kaya: 0.08

Unique Generic Manipulation sources:

Ghostship: -0.4

Spell Damage

D_{M}

:

{\begin{aligned}D_{M}&=\underbrace {(1-0.2-0.3+\overbrace {0.18} ^{\text{Spell Only}})} _{\text{Generic Incoming}}\times \underbrace {(1+\overbrace {0.3+0.08} ^{\text{Spell Only}})} _{\text{Generic Outgoing}}\times \underbrace {(1-0.4)} _{Unique}\\&=(0.68)\times (1.38)\times (0.6)\\&=56.304\%\end{aligned}}

Note that Magic Weakness, Bloodrage and Kaya's amplification only apply to spell damage, therefore another calculation will be needed for non-spell damage $D_{M}$ .

Non-Spell Damage

D_{M}

:

${\begin{aligned}D_{M}&=\underbrace {(1-0.2-0.3)} _{\text{Generic Outgoing}}\times \underbrace {(1)} _{\text{Generic Incoming}}\times \underbrace {(1-0.4)} _{\text{Unique}}\\&=(0.5)\times (1)\times (0.6)\\&=30\%\end{aligned}}$

In this example,

Spectre would take 56.304% spell damage and 30% damage from non-spell damage from the enemy in this scenario.

Example 2: Additive Stacking[]

All values in this section consider the highest possible level of an ability but exclude talents and aghanim's upgrades unless otherwise mentioned. Examples ignore armor and magic resistance.

Ursa is Enraged and is affected by Flesh Golem.

100% - 80% + 35% = 55% damage

Spectre with Dispersion and is affected by Stampede.

100% - 20% - 30% = 50% damage

A hero affected by Winter's Curse and Flesh Golem at the same time.

100% - 100% + 35% = 35% damage

Example 3: Other Multiplicative Stacking[]

All values in this section consider the highest possible level of an ability but exclude talents and aghanims upgrades unless otherwise mentioned. Examples ignore armor and magic resistance.

Medusa activated Mana Shield and is affected by Flesh Golem.

(100% + 35%) * (100% - 70%) = 40.5% damage

Medusa activated Mana Shield, is affected by Ghostship rum buff and is affected by Flesh Golem.

(100% + 35%) * (100% - 70%) * (100% - 40%) = 24.3% damage

A Conjure Image illusion (taking 300% damage) affected by Flesh Golem and Stampede

(100% + 35% - 30%) * 300% = 315% damage

Damage Negation[]

Damage negation causes entire instances of damage to deal no damage to its target, however, the instance is still registered. This means, if something reacts on damage without having a minimum damage threshold, it still reacts on the negated damage.

It is unknown whether these abilities use a separate mechanic to completely negate damage, or if they use the same unique damage manipulators as Ghostship and Mana Shield do, but with their values set to 100%.

Abaddon - Aphotic Shield

Negated Damage: 110/140/170/200 ( 210/240/270/300)
Duration: 15
Can only negate a certain amount of damage before detonating.
Abaddon - Borrowed Time

Duration: 4/5/6 ( 7/8/9)
Also turns the negated damage into heals for Abaddon.
Faceless Void - Backtrack

Chance: 20%
Infused Raindrops - Magical Damage Block

Negated Damage: 120
Charges: 6
Can only negate magical damage. Can only negate a certain amount of damage per charge. Goes on cooldown upon negating an instance. Ignores damage lower than 50.
Monkey King - Mischief

Duration: 0.2 ( 0.5)
Nyx Assassin - Spiked Carapace

Duration: 2
Can only negate one instance of damage from each player.
Omniknight - Guardian Angel

Duration: 5/6.5/8 ( 8/9/10)
Can only negate physical damage.
Oracle - False Promise

Duration: 7/8.5/10 ( 8.5/10/11.5)
The negated damage is dealt immediately once the buff ends.
Templar Assassin - Refraction
$Refraction icon.png$
Charges: 3/4/5/6 ( 10/11/12/13)
Duration: 17
Can only negate a certain number of damage instances. Ignores damage lower than 5.
Tinker - Defense Matrix

Shield Capacity: 100/180/240/320 ( 225/305/365/445)
Duration: 15
Void Spirit - Resonant Pulse

Base Negated Damage: 40/80/120/160
Bonus Negated Damage per Hit Hero: 30/45/60/70
Duration: 10
Can only negate a certain amount of damage. Can only negate physical attack damage.
Winter Wyvern - Cold Embrace

Duration: 4
Can only negate physical damage.

Preventing on-damage effects[]

Many abilities react on damage a unit receives. In some cases, fully negating the damage causes them to not proc. However, some on-damage effects also react on 0 damage so they still may proc even when the proccing damage got negated.

The following abilities and effects do not react on damage when it gets fully negated (reduced to 0):

¹ These work when the damage gets negated by Aphotic Shield.

² These abilities have damage counters, which do not work when the damage gets negated.

The following abilities still do react on fully negated damage:

Bane – Nightmare
Batrider – Sticky Napalm
Battle Fury – Cleave
Blade Mail – Damage Return
Chen – Divine Favor
Death Prophet – Exorcism
Dragon Knight – Elder Dragon Form (splash damage)
Elder Titan – Echo Stomp
Kunkka – Tidebringer
Lifestealer – Feast
Lone Druid – Summon Spirit Bear
Magnus – Empower
Spectre – Dispersion¹
Spirit Bear – Return
Sven – Great Cleave
Tiny – Tree Grab
Tiny – Tree Throw
Viper – Corrosive Skin
Warlock – Fatal Bonds¹

¹ The damage of Dispersion and the damage spread of Fatal Bonds are fully unaffected by any form of reduction, except for magic resistance and armor.

Min Health[]

Lina casting Laguna Blade on a low health Dazzle affected by Shallow Grave and Blade Mail.
Lina takes the full Laguna Blade damage.

Minimum Health, just like regular damage negation, prevents a unit from dying. However, the way in which that is achieved is completely different. Instead of directly reducing or negating damage, this mechanic rather manipulates the health of the unit. The MODIFIER_PROPERTY_MIN_HEALTH property prevents a unit's health from dropping below the value it is set to. It does not affect the damage itself, meaning on-damage effects react on the full damage, and not how much damage was dealt with effectively, so they can be triggered normally.

Min health does not prevent instant kill in anyway.

Min Health Sources

Dazzle - Shallow Grave

Min Health: 1
Duration: 2%/4%/6%/8%
Troll Warlord - Battle Trance

Min Health: 1
Duration: 6.5 ( )
Wraith King - Wraith Delay

Min Health: 1
Duration: 7
Affects all allied heroes within a 1200 radius. Once the min health is reached, the ally gets a buff that continues applying min health, for the given duration, followed by an ensured death.