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

• 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%
  Requires Aghanim's Shard 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: 40%
  Duration: 3.5/4/4.5 ( 4.5/5/5.5)
  Requires Aghanim's Scepter. Reduces all damage buffed allies take.
• Legion Commander - Duel
  
  Damage Reduction: 50%
  Duration: 4/4.75/5.5 ( 6/7/8)
  Requires Aghanim's Scepter. 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: 50%
  Requires Aghanim's Scepter to unlock. Reduces all damage Nyx Assassin takes while burrowed.
• 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.
• Ursa - Enrage
  
  Damage Reduction: 80%
  Duration: 4/4.5/5
  Reduces all damage Ursa takes while buffed.
• Visage - Gravekeeper's Cloak
  
  Max Layers: 4 ( 9)
  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.

There currently are no abilities that reduce outgoing damage using the generic damage manipulator.

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 Amplification 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%)
  Applies a buff on the caster or ally hero.
• Io - Overcharge
  
  Outgoing Spell Damage Amplification: 10%/12%/14%/16%
  Applies a buff on the caster and transfers to the Tethered ally as well.
• Mage Slayer - Mage Slayer
  
  Incoming Damage Reduction: 35%
  Duration: 6
  Reduces all spell damage dealt while affected by the debuff.
• 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.

Talents

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

Bonus	Level 10		Level 15		Level 20		Level 25
	Left	Right	Left	Right	Left	Right	Left	Right
Spell Amplification	+6% +6% +8%	+5% +8% +8%		+12% +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.

Outgoing Spell Damage Increasing Items (1% Spell Damage Amp per Point)

Item	Value	Item Cost	Cost/Value Point
Bloodstone	8	5750	718.75
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
Null Talisman	3	505	168.33
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.
• Omniknight - Hammer of Purity
  
  Damage Reduction: 60%
  Duration: 4
  Requires Aghanim's Shard to be unlocked. Reduces all damage the target deals.

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 DM is defined as

$D_{M}={\Big (}1+\sum _{i=1}^{n}{I_{i}}{\Big )}\times {\Big (}1+\sum _{i=1}^{n}{O_{i}}{\Big )}\times \prod _{i=1}^{n}{U_{i}}$

With I being any Incoming Generic Manipulation, O being any Outgoing Generic Manipulation, and U being any Unique Damage Manipulation. As there cannot be a negative value for damage manipulation, use 0 as a value in those cases.

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 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: -0.4, Magic Weakness: 0.18.

Outgoing Generic Manipulation sources: Bloodrage: 0.3, Kaya: 0.08

Unique Generic Manipulation sources: Ghostship: -0.4

Spell Damage $D_{M}$:

${\begin{aligned}D_{M}&=(1-0.2-0.4+\underbrace {0.18)\times (1+0.3+0.08} _{\text{Spell Dmg Amp Sources}})\times (1-0.4)\\&=48.024\%\end{aligned}}$

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 $D_{M}$:

${\begin{aligned}D_{M}&=(1-0.2-0.4)\times 1\times (1-0.4)\\&=24\%\end{aligned}}$

In this example, Spectre would take 48.024% spell damage and 24% 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. 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% - 40% = 40% 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. 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 320% damage) affected by Flesh Golem and Stampede

(100% + 35% - 40%) * 320% = 304% 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
  
  Charges: 3/4/5/6 ( 11/12/13/14)
  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 ( 250/330/390/470)
  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):

• Aegis of the Immortal – Expire Restore
• Ancient Black Dragon – Splash Attack¹
• Blink Dagger – Blink
• Bloodthorn – Soul Rend
• Bottle – Regenerate
• Bristleback – Bristleback²
• Clarity – Replenish
• Healing Salve – Salve
• Lifesteal – All sources
• Lifestealer – Open Wounds
• Mjollnir – Static Charge
• Monkey King – Tree Dance
• Orchid Malevolence – Soul Burn
• Pugna – Life Drain
• Regeneration Rune – Regeneration
• Spell Lifesteal – All sources
• Spirit Vessel – Soul Release
• Templar Assassin – Psi Blades¹
• Tidehunter – Kraken Shell²
• Urn of Shadows – Soul Release
• Visage – Soul Assumption²

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: 4/4.5/5/5.5
  
• Troll Warlord - Battle Trance
  
  Min Health: 1
  Duration: 6.5 ( 8.5)
  
• 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.

Mechanics Stats Armor Attributes ( Strength / Agility / Intelligence) Collision size Health (Health regeneration) Magic resistance Mana (Mana regeneration) Movement speed Status resistance Turn rate Vision Gib type Legs Attack Attack animation Attack damage (Heroes) Attack modifier (Bash / Cleave & Splash / Critical strike / Lifesteal / Mana break) Attack range Attack speed Cast animation Cast range Damage types Projectile speed Spell damage Spell lifesteal Abilities Abilities Aura Channeling Cooldown Damage block Damage manipulation Damage over time Evasion Talents Teleport Status effects Attack immunity Break Cyclone Disable Disarm Ethereal Fear Forced movement Hex Hide Hypnosis Invisibility Invulnerability Leash Phased Root Silence Sleep Slow Spell immunity Stun Taunt World Experience Gold Glyph of Fortification Map (Minimap) River Scan Runes Time of day Trees Gameplay Creep control techniques Denying Disjoint Dispel Ganking Harassment Hero complexity Initiating Item passive stacking Item sharing Jungling Lane Pushing Random distribution Roles Trap Units Ancient creeps Buildings Couriers Creep-heroes Heroes Illusions Lane creeps Neutral creeps Roshan Summons & Wards