Viper/Counters

Bad against...

 * As Viper's damage is entirely single-target, puts him at a severe disadvantage.
 * lets Arc Warden kill Viper more quickly while evading his attacks.
 * Viper's low movement speed makes him vulnerable to Arc Warden's slows.


 * 's pure damage bypasses Corrosive Skin and weakens Nethertoxin.
 * fully negates Viper's poison damage and slows.
 * negates Viper's physical damage output.


 * facilitates early ganks with its long-range slow and damage.
 * can be used to counter-push quickly against Viper.
 * Viper's single-target physical damage can be negated by.
 * can make Viper potentially kill one of his teammates or lock Viper himself down.


 * strips away Viper's Agility-based armor and Corrosive Skin's magic resistance.
 * and 's mixed damage combines well with Natural Order to quickly kill Viper.


 * evades Poison Attack and counteracts the slow.
 * Viper's low mobility makes him an easy target.
 * grants Windranger significant physical damage output to quickly wear Viper down.
 * is a strong harassment and zoning tool against Viper in lane.


 * and can quickly kill Viper through Corrosive Skin.


 * weakens Nethertoxin and severely reduces Viper's damage output.
 * 's Pure Damage ignores Corrosive Skin.
 * Viper cannot interrupt.


 * deals pure damage and prevents Poison Attack harassment in lane.
 * with and  can prevent Viper from pushing while wearing him down.
 * with and  allow Tinker to keep away from Viper's retaliation.


 * can render Viper useless, and he has no way of interrupting it.
 * 's high physical damage quickly wears Viper down.


 * Corrosive Skin provides little protection against early on.
 * Viper's lack of area damage means he can do little against a swarm of Spiderlings.
 * Broodmother can bring Viper down quickly with activated.


 * is flagged as HP Removal, fully ignoring Corrosive Skin, and greatly reduces Viper's longevity.
 * 's regeneration and spammable heal counteracts Viper's damage over time.


 * ed Neutral creeps can be used to pressure Viper in lane, and Enchant's slow prevents Viper from fleeing.
 * is a powerful heal and can save teammates from Viper's attacks.
 * makes Enchantress much harder to kill.
 * 's heavy Pure Damage ignores Corrosive Skin and kills Viper quickly.


 * and can be used to kite and escape from Viper.
 * and deal heavy damage and can quickly bring Viper down.
 * ,, and are powerful disables that reduce Viper's effectiveness.
 * burns Viper's limited mana pool, reducing his potential poison damage.
 * s can melt Viper's armor and reduce his durability.


 * While Ursa can be kited by Viper, he can quickly kill Viper if he initiates.
 * removes Viper's slows and makes Ursa highly resiliant to damage.
 * slows Viper, making it difficult to escape.


 * ignores slows and allows Weaver to escape Viper's onslaught.
 * dispels and  and undoes poison damage.
 * Weaver's high burst damage allows him to kill Viper before being killed.


 * Viper's single-target damage over time and lack of disables makes him easy to.
 * 's physical damage is mitigated by Terrorblade's high armor.
 * Terrorblade under can quickly kill Viper with heavy physical damage.

Others

 * Viper cannot interrupt heroes with powerful channeling abilities:, ,.
 * Heroes with a built-in haste can ignore Viper's slows:,.
 * Illusion-based heroes can confuse Viper and often disjoint Viper Strike:, ,.
 * Heroes with high Physical or Pure burst damage can kill Viper before his damage over time sets in.
 * Heroes that can drain mana negatively affect Viper's ability to use Poison Attack and Viper Strike:, ,.

Items

 * allows heroes to escape from Viper, as he cannot interrupt it nor kill a healthy hero before they teleport.
 * can be used to take advantage of Viper's low mobility, but his damage over time makes it somewhat unreliable for escape.
 * and protect against Viper's attacks.
 * 's invisibility prevents Viper from attacking the target, and the magic resistance counteracts Viper's damage over time.
 * can allow a hero to escape while slowed by Viper.
 * 's Break disables Nethertoxin and Corrosive Skin.
 * disjoints Viper Strike and can make Viper waste time attacking illusions.
 * can slow Viper with its active ability and pin him down while burning his mana.
 * summons are difficult for Viper to fight against and burn his mana.
 * blocks Viper Strike, and Viper has no other ways to break the Spell Block.
 * can reflect Viper Strike.

Good against...

 * Zeus is extremely fragile and can easily be bullied in lane with Poison Attack.
 * Corrosive Skin severely reduces Zeus's damage output.


 * Viper's damage over time quickly burns through charges.
 * Templar Assassin's short range, aside from spill damage, makes her vulnerable to Poison Attack harassment.


 * Corrosive Skin protects Viper from Queen of Pain's Magic Damage arsenal while inflicting comparable damage in return.
 * Poison Attack allows Viper to harass Queen of Pain in lane.


 * As a melee hero with low mobility, Dragon Knight can be easily harassed by Poison Attack.
 * Corrosive Skin protects Viper from.
 * Viper's damage over time wears Dragon Knight down more quickly than Dragon Knight can damage Viper, even with.


 * While both specialize in poison damage, Corrosive Skin means Viper can often kill Venomancer before Venomancer kills him.

Others

 * Melee heroes with low mobility can be kited and killed by Viper:, , , , , , ,.
 * Heroes reliant on Magical Damage cannot easily break Viper down due to Corrosive Skin.

Works well with...

 * greatly increases Viper's attack damage, making his laning phase even stronger.
 * and combined with Viper's slows make it very difficult for an enemy to escape.


 * provides easy targets for Viper to pick off from a distance.


 * can help Viper catch up with enemies.
 * and amplify Viper's damage output.
 * If Vengeful Spirit dies, the negative makes Viper harder for the enemy to bring down.


 * interrupts channeling abilities and can lock down a target for Viper to kill.
 * further improves Viper's single-target damage.


 * and increases Viper's attack and movement speeds while providing further durability.
 * makes up for Viper's lack of mobility.


 * can quickly wear down enemies' health, letting Nethertoxin kick in sooner.
 * further slows Viper's prey and provides regeneration.
 * provides a nasty surprise for enemies initiating on Viper.

List of heroes that counter Viper, and list of heroes that work well with Viper.