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Viper icon.png
Strength attribute symbol.png
Agility attribute symbol.png
Intelligence attribute symbol.png
21 + 2.4
21 + 2.7
17 + 2
Level 0 1 15 25 30
Health 200 620 1280 2000 2280
+0.25 +2.35 +5.71 +9.31 +10.71
Mana 75 279 615 999 1143
+0 +0.85 +2.25 +3.85 +4.45
Armor -2 1.5 7.8 14.3 16.88
Damage Block -
Magic Resistance 25%
Status Resistance 0%
Damage 27‒29 48‒50 85‒87 124‒126 140‒142
Attack Rate 0.71/s 0.83/s 1.05/s 1.28/s 1.37/s
Attack Range Ranged 575 (800)
Attack Speed ▶️ 120 (1.7s BAT)
Attack Animation 0.33+1
Projectile Speed 1200
Movement Speed ▶️ 275
Turn Rate Takes 0.175s to turn 180°. 0.6
Collision Size 24
Vision Range (G) 1800 • 800
Legs 0
Gib Type Goo
Ability Upgrades
Upgradable by Aghanim's Scepter.
Upgradable by Aghanim's Shard.
Viper Strike
Poison Attack
Poisonous toxins chip away armor and slow enemies.
It was foolhardy to try and tame a Netherdrake, a lesson the old wizard learned in death. Freed from his captor, Viper spread his wings and went forth to explore the surface world. With Poison Attacks imbued with innocuous liquid, causing joints to harden, crippling foes whether they choose to flee or fight. Nethertoxin spreads throughout their bodies, turning wounds into fatalities, and fatigue into death. The Netherdrake's tough, Corrosive Skin protects against spell-craft, and burns assailants with acid. But it is the dreaded Viper Strike that signals the beginning of the end. The afflicted victim staggers to a crawl, barely able to take its next step. If the Netherdrake doesn't finish his targets off, the venom in their veins will.
Poison Attack
Poison Attack
Corrosive Skin
Viper Strike
Viper Strike
Roles: Carry Carry Durable Durable Initiator Initiator Disabler Disabler
Complexity: ★☆☆


Viper minimap icon.pngViper, the Netherdrake
▶️ "You've failed the acid test."
The malevolent familiar of a sadistic wizard who captured and hoped to tame him, Viper was curiously glad to have been sprung from the sealed and unchanging subterranean Nether Reaches where his race had lived for millions of years, after tectonic slippage had sealed off the Netherdrakes in luminous caverns. Viper spent some time appearing to submit to the wizard's enchainments, hoping to learn what he could of the dark magics the mage practiced. But he soon realized that few spells were as deadly as the toxins that were his birthright. Exuding an acid that swiftly ate away the bars of his cage, the Netherdrake slipped free of his confines, spit poison in the old spellcaster's eyes, and soared out to let the world know that it had a new master.


Poison Attack
Poison Attack icon.png
Intensifies Viper's venom, adding an effect to his normal attack that applies a stacking movement speed slow and magic resistance deduction while dealing damage over time. Stacks up to 5 times.
Cast Range: 600/640/680/720
Max Stacks: 5 (With Aghanim's Shard 8)
Damage per Second per Stack: 4/8/12/16
Move Speed Slow per Stack: 6%/8%/10%/12%
Magic Resistance Reduction per Stack: 4%/6%/8%/10% (Talent 12%/14%/16%/18%)
Duration: 4
With Aghanim's Shard Armor Reduction per Stack: 1
With Aghanim's Shard Building Damage Percentage: 40%
Cooldown: 0
Mana: 18/20/22/24
Upgradable by Aghanim's Shard.
Aghanim's Shard Upgrade:
Increases max stacks, and causes Poison Attack to lower armor per stack and to affect buildings for reduced damage.
Modifiers [?]
The Netherdrake's inborn toxic breath quickly drains the vitality of its afflicted.


  • The cast range of Poison Attack is based on the attack range of the caster.
    • The cast range can be further increased by other attack range bonuses. However, it is not affected by cast range bonuses.
    • Both Autocast and manually casting it uses Viper's current attack range.
  • Poison Attack places one debuff on the target, successive attacks increase its stack count, and resets the duration of the entire stack.
    • Does not work against allied units or wards.
    • The number of stacks can be seen on the status buff icon as well.
  • With 5 (Upgradable by Aghanim's Shard. 8) stacks, it reduces the enemy target's movement speed by 30%/40%/50%/60% (Upgradable by Aghanim's Shard. 48%/64%/80%/96%).
    • It also reduces the enemy target's magic resistance to 10%/2.5%/-5%/-12.5% (Upgradable by Aghanim's Shard. 1%/-11%/-23%/-35%).
    • With the magic resistance reduction increasing Talent talent, it reduces the enemy target's magic resistance to -47%/-59%/-71%/-83%.
    • For how much movement speed and magic resistance Poison Attack reduces with a certain amount of stacks on each level, please refer to the chart below.
  • Deals damage in 1-second intervals, starting 1 second after the debuff is applied, resulting in 4 damage instances.
    • With max stacks, Poison Attack can deal up to 20/40/60/80 (Upgradable by Aghanim's Shard. 32/64/96/128) damage per second, and a total of 80/160/240/320 (Upgradable by Aghanim's Shard. 128/256/384/512) damage in 4 seconds.
    • For how much damage per second and total damage Poison Attack deals with a certain amount of stacks on each level, please refer to the chart below.
  • The attacks first apply the debuff, then their own damage.
  • With Aghanim's Shard icon.png Aghanim's Shard, Poison Attack reduces armor and also applies its effects on buildings as well.
    • Reduces armor by 1/2/3/4/5/6/7/8 per stack.
    • With max stacks, Poison Attack reduces all affected buildings' total magic resistance to -32%/-48%/-64%/-80% (Talent -96%/-112%/-128%/-144%)
    • This means it can deal up to 16.9/37.89/62.98/92.16 (Talent 25.09/54.27/87.55/124.93) damage per second to buildings.

Nethertoxin icon.png
Viper releases a Nethertoxin at the targeted area. Units in that area take an increasing damage over time based on how long they remain in it. Disables passives of affected units.
Cast Animation: 0.2+0.5
Cast Range: 900
Radius: 400
Min Damage per Second: 15/20/25/30 (Talent 55/60/65/70)
Max Damage per Second: 50/75/100/125 (Talent 90/115/140/165)
Max Damage Duration: 4
Damage Interval: 0.5
Aura Linger Duration: 0.5
Duration: 8
Cooldown: 14 (Talent 3)
Mana: 85
Modifiers [?]
Poison from the Nether Reaches turns wounds into fatalities, and fatigue into death.


  • Nethertoxin's projectile travels at a speed of 2000.
  • All effects of Nethertoxin, including the damage per interval, are provided by an aura. Its debuff lingers for 0.5 seconds.
  • Deals damage in 0.5-second intervals, starting 0.5 seconds after receiving the debuff, resulting in up to 17 instances.
  • The damage increases by 2.19/3.44/4.69/5.94 for each 0.5 seconds spent within the area.
    • As the damage increases per interval, and once it reaches the maximum 25/37.5/50/62.5 (Talent 45/57.5/70/82.5) damage per interval, the damage at subsequent intervals deal the maximum damage, until the end of its duration.
    • Can deal up to 346.25/513.75/681.25/848.75 (Talent 686.25/853.75/1021.25/1188.75) damage within the area for the entire duration.
    • For how much damage per interval Nethertoxin deals, with the damage increasing Talent talent, please refer to the chart below.
  • The damage value resets whenever the enemy leaves the radius and enters it again. It does not count accumulated time spent within the radius.
  • Leveling up the ability or the damage increasing Talent talent does not update the damage of already placed debuffs.
    • However, if the debuff is applied after leveling the ability or the talent, the affected enemy takes the new damage values.
  • Multiple instances of Nethertoxin's debuff do not stack.

Corrosive Skin
Corrosive Skin icon.png
Self / Enemies
Viper exudes an infectious toxin that damages and slows the attack speed of any enemy that damages it in a 1400 radius. The acid exudate also increases Viper's resistance to magic.
Max Proc Distance: 1400
Magic Resistance Bonus: 10%/15%/20%/25% (Talent 20%/30%/40%/50%)
Damage per Second: 8/16/24/32 (Talent 21/29/37/45)
Attack Speed Slow: 8/16/24/32 (Talent 16/32/48/64)
Duration: 4
Can be used by illusions.
Illusion Notes:
Illusions do not benefit from the bonus magic resistance.
Modifiers [?]
It is not unusual for sword and shield alike to corrode in the very hands of those who attack the Netherdrake.


  • The damage and attack speed slow debuff is applied to whoever damages Viper within 1400 range.
  • Corrosive Skin procs on all 3 damage types, but not self-inflicted damage and HP Removal effects (e.g. Sunder, Soul Ring icon.png Soul Ring etc.).
    • Damage procced is dealt to the damage source itself. This means, damage dealt by abilities that are not sourced from the caster (e.g. Proximity Mines), do not trigger Corrosive Skin debuff on the caster.
    • The damage dealt has the no-reflection flag, preventing its damage from interacting with other sources of damage with the same flag.
  • Deals damage in 1-second intervals, starting 1 second after the debuff is applied, resulting in 4 damage instances.
  • Successive procs of Corrosive Skin on the same target do not stack, only the debuff gets refreshed.

Viper Strike
Viper Strike icon.png
Viper slows the targeted enemy unit's movement and attack speed while also dealing poison damage over time. The slowing effect reduces over the duration of the poison.
Cast Animation: 0.3+0.53
Cast Range: 500 (With Aghanim's Scepter 900)
Damage per Second: 80/120/160 (Talent 160/200/240)
Move Speed Slow: 40%/60%/80%
Attack Speed Slow: 40/60/80
Duration: 5
Cooldown: 50/40/30 (With Aghanim's Scepter 10)
Mana: 100/150/200 (With Aghanim's Scepter 125)
Upgradable by Aghanim's Scepter.
Aghanim's Scepter Upgrade:
Decreases mana cost and cooldown, and increases cast range.
Blocked by Linken's Sphere.
Blocked upon impact.
Modifiers [?]
Once used to slay his sadistic summoner, the most powerful of Netherdrake infections spreads through the veins of those foolish enough to cross Viper.


  • Viper Strike's projectile travels at a speed of 1200.
  • The slow decreases over time. Affected units regain 0.3%/0.4%/0.5% of their movement speed and 0.267/0.4/0.533 attack speed on each server tick.
    • This equals to 8%/12%/16% movement speed and 8/12/16 attack speed regained per second.
  • Deals damage in 1-second intervals, starting immediately as the debuff is applied, resulting in 5 damage instances.
  • Successive casts of Viper Strike on the same target do not stack, only the debuff gets refreshed.
  • The particle effects on Viper's wings during the cast time are visible to everyone, showing that the ability is being cast.

Poison Attack Calculations[]

All values below are to be considered before reductions and amplifications.

Units Movement Speed Movement Speed Slow/ Stack
Level / Stack Base 2nd 3rd 4th 5th Upgradable by Aghanim's Shard. 6th Upgradable by Aghanim's Shard. 7th Upgradable by Aghanim's Shard. 8th
Level 1 6% 12% 18% 24% 30% 36% 42% 48%
Level 2 8% 16% 24% 32% 40% 48% 56% 64%
Level 3 10% 20% 30% 40% 50% 60% 70% 80%
Level 4 12% 24% 36% 48% 60% 72% 84% 96%
Units and Buildings Magic resistance Magic Resistance Reduction/ Stack
Level / Stack Base 2nd 3rd 4th 5th Upgradable by Aghanim's Shard. 6th Upgradable by Aghanim's Shard. 7th Upgradable by Aghanim's Shard. 8th
Level 1 4% 8% 12% 16% 20% 24% 28% 32%
Level 2 6% 12% 18% 24% 30% 36% 42% 48%
Level 3 8% 16% 24% 32% 40% 48% 56% 64%
Level 4 10% 20% 30% 40% 50% 60% 70% 80%
Damage per Second/ Stack and Σ Damage for the Entire Duration
Level / Stack Base 2nd 3rd 4th 5th Upgradable by Aghanim's Shard. 6th Upgradable by Aghanim's Shard. 7th Upgradable by Aghanim's Shard. 8th
Level 1 DPS 4
(Σ 16)
(Σ 32)
(Σ 48)
(Σ 64)
(Σ 80)
(Σ 96)
(Σ 112)
(Σ 128)
Level 2 DPS 8
(Σ 32)
(Σ 64)
(Σ 96)
(Σ 128)
(Σ 160)
(Σ 192)
(Σ 224)
(Σ 256)
Level 3 DPS 12
(Σ 48)
(Σ 96)
(Σ 144)
(Σ 192)
(Σ 240)
(Σ 288)
(Σ 336)
(Σ 384)
Level 4 DPS 16
(Σ 64)
(Σ 128)
(Σ 192)
(Σ 256)
(Σ 320)
(Σ 384)
(Σ 448)
(Σ 512)
Units and Buildings Armor Armor Reduction/ Stack
Upgradable by Aghanim's Shard. All Levels / Stack 1 2 3 4 5 6 7 8

Nethertoxin Calculations[]

All values below are to be considered before reductions and amplifications.

Nethertoxin Damage/ Interval Calculations with Talent damage increasing Talent
Duration/ Level 0.5s 1s 1.5s 2s 2.5s 3s 3.5s 4s 4.5s 5s 5.5s 6s 6.5s 7s 7.5s 8s
Level 1
Level 2
Level 3
Level 4


Hero Talents
2x Corrosive Skin Slow and Resistance25-11s Nethertoxin Cooldown
+8% Poison Attack Magic Resistance Reduction20+80 Viper Strike DPS
+300 Health15+40 Nethertoxin Min/Max Damage
+13 Corrosive Skin Damage10+20 Attack Speed
  • The health talent increases maximum health capacity, and keeps the current health percentage.

Recent Changes[]

Main Article: Viper/Changelogs
Level 10 left talent changed: 8% spell lifesteal ➜ +13 Corrosive Skin damage per second.
Level 15 right talent changed: +70 Nethertoxin max damage per second ➜ +40 Nethertoxin min/max damage.
Level 20 left talent changed: +70 attack damage ➜ +8% Poison Attack magic resistance reduction per stack.
  • Increased Agility attribute symbol.png agility gain from 2.5 to 2.7.
  • Increased Poison Attack magic resistance reduction per stack from 3%/5%/7%/9% to 4%/6%/8%/10%.
Level 15 right talent changed: +100 attack range ➜ +70 Nethertoxin max damage per second.

Recommended Items[]

Starting items:

Early game:

  • Boots of Speed icon.png Boots of Speed are a standard pickup that give movement speed.
  • Wraith Band icon.png Wraith Band provides a decent boost to Viper's attributes. The extra damage and attack speed help him secure last hits.
  • Infused Raindrops icon.png Infused Raindrops adds extra mana regeneration and protection against magical damage.
  • Magic Wand icon.png Magic Wand offers burst health and mana.

Mid game:

  • Arcane Boots icon.png Arcane Boots expand his mana pool, allowing him to use abilities more often inside and outside of combat.
  • Rod of Atos icon.png Rod of Atos gives Viper access to a root, greatly enhancing his ganking power, as well as much-needed stats. The components also provide a convenient build up for him in the early game

Late game:

  • Guardian Greaves icon.png Guardian Greaves, the upgrade to Arcane Boots, make Viper exceptionally tanky. The active restores a large portion of health and mana to the entire team while dispelling debuffs; the passive prevents low health heroes from succumbing to their wounds. The extra survivability keeps Viper alive far longer, allowing him to sustain his allies and deal more damage.
  • Aghanim's Scepter icon.png Aghanim's Scepter lowers his ultimate's cooldown to 10 seconds and cuts the mana cost in half. Viper can now cast it multiple times in an engagement for offensive or defensive purposes.

Situational items:

  • Veil of Discord icon.png Veil of Discord enhances the magical damage of Viper's entire kit as well as granting attributes and armor.
  • Shadow Blade icon.png Shadow Blade is a good pickup on Viper if you intend to seize map control. Viper is a very capable ganker if he can get close to a target. Between both of his slows and his damage scaling up as his target's health decreases, he is very good at 1v1 dueling.
  • Heaven's Halberd icon.png Heaven's Halberd can be an idiosyncratic yet effective choice against teams that rely on damage from 1-2 right-click heroes. Halberd stops those opponents from attacking in addition to granting status resistance and evasion.
  • Sange and Yasha icon.png Sange and Yasha is a common pickup in the midgame. Viper enjoys the additional health and damage, as well as movement speed.
  • Black King Bar icon.png Black King Bar grants spell immunity so Viper can act without worrying about most enemy disables.
  • Monkey King Bar icon.png Monkey King Bar provides magical damage on top of a solid chunk of damage and a little attack speed. It's best suited against enemy carries who are picking up evasion items and heroes with blind.
  • Nullifier icon.png Nullifier shuts down heroes who rely on items. Viper by nature struggles against mobility items like Force Staff icon.png Force Staff and Blink Dagger icon.png Blink Dagger; he is also vulnerable to disables from Orchid Malevolence icon.png Orchid Malevolence and Scythe of Vyse icon.png Scythe of Vyse. Nullifier also stops targets from activating Black King Bar icon.png Black King Bar, Glimmer Cape icon.png Glimmer Cape and other items that counteract his magic damage.
  • Manta Style icon.png Manta Style provides a mix of tankiness, damage, and chasing potential. Mirror Image dispels certain debuffs that cripple Viper's playstyle. Since Corrosive Skin carries over to illusions, it is moderately useful for split-pushing.
  • Mjollnir icon.png Mjollnir is one of the best DPS items for Viper in the lategame. It accentuates his waveclear, adds more magical damage with the active as well as the passive (this damage is greatly amplified under effect of Poison Attack), and provides high attack speed to enhance Poison Attack.
  • Heart of Tarrasque icon.png Heart of Tarrasque increases Viper's tankiness. Combined with Corrosive Skin and Guardian Greaves, Viper becomes incredibly hard to put down.
  • Eye of Skadi icon.png Eye of Skadi is ideal for Viper players who want to frontline. It gives him great stats across the board and the duration of Cold Attack almost perfectly overlaps Poison Attack. The combined attack speed and move speed slows of Viper's abilities and Skadi's modifier will slow any target to a crawl.
  • Bloodthorn icon.png Bloodthorn prevents spellcasters from using spells, as well as making your targets more vulnerable to your DPS. The mana regeneration also remedies Viper's constant lack of mana.
  • Octarine Core icon.png Octarine Core combines well with Viper as he can output high magical damage, specifically from Nethertoxin. The spell lifesteal makes this already tanky hero even harder to kill, and stacks with his spell lifesteal talent to provide significant healing. Extra health and mana also allow Viper to live longer and cast more spells during teamfights. Finally, the cooldown reduction allows for more uses of Nethertoxin and Viper Strike, especially when paired with Aghanim's Scepter.
  • Radiance (Active) icon.png Radiance is an item to consider on Viper as he is a durable hero who will survive in fight long enough to deal damage over time to his enemies. Combined with spell lifesteal, it adds to his innate tankiness and the damage also allows him to attack enemies with Poison Attack more effectively.






  • Viper's response ▶️ "Holy shit, it's me!" is a reference to a scene of the movie Top Gun.[1] Gyrocopter minimap icon.png Gyrocopter makes a similar, yet more accurate ▶️ response upon meeting him as an ally.
  • Viper's Chinese name is 冥界亚龙 (Míngjiè Yàlóng), a literal translation of "Netherdrake". However, Viper Strike's translation still uses the word "Viper" (蝮蛇, fùshé).