* Nethertoxin prevents buildup of Fiery Soul stacks.
* Corrosive Skin provides magic resistance against Lina's spells.
* Poison Attack and Viper Strike can burn away Lina's small health pool.

* Arcane Curse discourages Lina from using her abilities, preventing her from building up Fiery Soul stacks.
* Last Word and Global Silence are great against Lina for the same reason, as well as interrupting her combos and preventing her from casting spells.

* Nethertoxin disables Bristleback's passive.
* Viper Strike and Poison Attack slow down Bristleback's movement speed so he's unable to get out from Nethertoxin.
Additional:
* Nethertoxin's break removes Bristleback and prevents Warpath from building stacks. Besides losing his eponymous defensive passive, Bristleback also lose his ability to build up damage over lengthy battles.
* Viper can perpetually kite Bristleback with Poison Attack and Viper Strike.

* Arcane Curse stacks every time Bristleback uses an ability, forcing him to stop spamming his abilities, or take heavy health degeneration.
* Glaives of Wisdom steals intelligence both permanently and temporarily, causing mana issues for Bristleback .
* Last Word and Global Silence stops Bristleback from using his abilities altogether.
Additional:
* Bristleback will not be able to cast Viscous Nasal Goo or Quill Spray while silenced, effectively blocking a major part of the hero's damage and preventing Warpath charges from stacking.
* Arcane Curse slows Bristleback down and lasts longer the more abilities he uses. On the other hand, if he doesn't use any abilitiess, he will begin to lose Warpath charges.

* Nethertoxin prevents Timbersaw from gaining stacks on Reactive Armor with silence talent also prevents Timbersaw using his abilities.

* Arcane Curse deals repeated stacks of damage to Timbersaw because he relies on constantly using his abilities.
* Glaives of Wisdom deals pure damage and when cast manually, nearby creeps will not attack silencer, making it an effective harassment tool.
* Although Last Word takes a while to trigger, it will break Timbersaw's ability combo and can be used to silence him.
* Global Silence will silence Timberaw no matter where he is on the map. This can be used to help allies get a kill on him, or prevent Timbersaw from killing someone.
Additional:
* Timbersaw is heavily reliant on his abilities for damage and escape, allowing Silencer to effectively disable him and make him useless in both team fights and 1v1 scenarios.

* Silencer's Global Silence will render Zeus useless for 6 seconds in a team fight.
* Arcane Curse will punish Zeus for casting spells, which can cause continuous damage to him should he continue to cast spells.
* Last Word can silence Zeus and prevent him from spamming his spells.
* Silencer often builds Orchid Malevolence (or Bloodthorn) which can be used on spell casters like Zeus, forcing him to invest in a Linken's Sphere.
Additional:
* Zeus' main source of damage is his low cooldown, high damage spells - meaning Last Word and Global Silence will pretty much take him out of the game for the duration.
* Zeus likes to spam his abilities, which makes him vulnerable to Arcane Curse.
* If Zeus dies near Silencer, he will lose intelligence, reducing his mana pool, mana regen and attack damage. Furthermore, if the game is long and Zeus dies often, the intelligence losses will also reduce his spell damage.

* Corrosive Skin counters Zeus in lane by canceling the effects of Clarity as Zeus relies on Arc Lightning to farm and secure last hits.
* Corrosive Skin also increases Viper's magic resistance to shrug off Zeus's magical nukes.
* Nethertoxin breaks Static Field.
* Due to Zeus' poor mobility, Viper Strike will cripple Zeus and will allow Viper and his teammates to land a lot of attacks.
Additional:
* Corrosive Skin severely reduces Zeus's damage output throughout the game.
* During the laning stage, Viper can abuse Zeus' reliance on spells by hugging the creep wave. Zeus will take constant damage over time from Corrosive Skin unless he drives Viper from the lane or returns to farming in his absence.
* Prior to buying Blink Dagger or Force Staff, Zeus is fragile and possesses low mobility. Any of Viper's numerous slows can set up an easy kill.

* Corrosive Skin gives Viper additional resistance to Phoenix's magical damage, and since they deal damage over time, Phoenix would be constantly afflicted by his passive's own debuff, making him not an ideal target for Phoenix's harassment. Phoenix's abilities also constantly drain its own health away, becoming more vulnerable to Poison Attack.

* Silencer will most likely disrupt an initiation with his ultimate, Global Silence, prevent escape with his Last Word, and if Phoenix happens to die to him (or near him) enough times, he would sap enough of Phoenix's much needed Intelligence to make him a stronger foe and Phoenix with less mana than it already had.

* Arcane Curse punishes Necrophos if tries to spam Death Pulse, increasing the duration of the slow and damage taken over time.
* Last Word heavily damages Necrophos and also silence him for a lenghty duration.
* Glaives of Wisdom will reduce temporarily Necrophos intelligence on each hit dealing hindering his ability to spam Death Pulse, also reducing his attack damage and mana pool; dealing increasing amounts of phisical and pure damage each time. Silencer will permanently steal Necrophos intelligence if killed by him or dies nears him.
* Global Silence turns Necrophos almost useless for a long time, allowing your team to easily dispatch him, since he heavily relies on his spells to survive.

* Nethertoxin prevents Heartstopper Aura from dealing damage or healing Necrophos.
* Viper's magic damage is amplified whenever Ghost Shroud is used.
* Corrosive Skin makes Viper tankier against Death Pulse and Reaper's Scythe.

* Kunkka relies on his powerful AOE spells to turn the tides of teamfights. He cannot use them while silenced.
* Last Word can mess up Kunkka's ability synergy, silencing him in the middle of his strong combo.
* Global Silence can disable Kunkka's spell casting from anywhere on the map, even if Kunkka is spell immune at the time.

* Melee heroes with low mobility can be kited and killed by Viper: Treant Protector, Kunkka, Alchemist, Troll Warlord, Wraith King, Tiny, Sven.

* Heroes with silences : Bloodseeker, Riki, Silencer.

* Corrosive Skin minimizes the damage Viper takes from all of Disruptor's skills.

* Heroes who can easily harass Crystal Maiden out of lane in the early game (Clinkz, Viper) can prevent Crystal Maiden from being able to level effectively, and can ultimately slow down her level 6, 12, and 18 to a point where enemy carries already have items to address her ultimate.

* Crystal Maiden is squishy, is heavily spell reliant, has low base Intelligence, and is naturally slow, making her an ideal target for Silencer
* Crystal Maiden's Freezing Field has a similar cooldown to Global Silence, therefore, Freezing Field can almost always be canceled to ruin aggressive Crystal Maiden initiations.

* Silencer's Global Silence and Doom's Doom makes Earthshaker temporarily useless.

* Poison Attack and Viper Strike allowing to kite and slow Earthshaker significally, putting Blink Dagger on cooldown and preventing him from initiating or re-initiating.
* Nethertoxin breaks Aftershock. The silence from Level 25 talent also prevents Earthshaker from initiating or re-initiating.
Additional:
* Being a melee hero, Earthshaker's movement is liable to suppression by Poison Attack and Viper Strike.
* Earthshaker's kit, with the exception of Enchant Totem, deals magic damage. Corrosive Skin effectively blunts his killing potential with a standard Blink combo among other things.
* Nethertoxin disables Aftershock, which removes the stun and bonus damage from Enchant Totem and Echo Slam. Additionally the level 25 talent will silence Earthshaker, making him vulnerable to Viper's teammates without stuns.

* Global Silence takes Omniknight out of the fight completely.
* Glaives of Wisdom are a great harass vs Omniknight during the laning stages of the game, since it doesn't aggro creeps & ignores his high base armor. It deals pure damage, which means it can also go through Guardian Angel.
* Silencer's intelligence steal can also cause Omniknight to falter in the early phases as it reduces his ability to use his spells.

* Heroes who can harass Omniknight out of lane will keep him weak in the mid game: Viper, Venomancer, Clinkz

* Heroes with silence and mana drain abilites, as Ancient Apparition relies entirely on his abilities: Invoker, Silencer, Nyx Assassin, Skywrath Mage, Shadow Shaman, Lion and etc.

* Corrosive Skin minimizes the damage Viper takes from all of Ancient Apparition's abilities.
* Ancient Apparition's slow movement speed, squishy nature, and lack of escape abilities can easily be taken advantage of through Poison Attack and Viper Strike.

* Because Poison Attack has a low cooldown at all levels, Aphotic Shield is ineffective as a hard dispel.
* Nethertoxin prevents Borrowed Time from activating passively and blocks Curse of Avernus

* Heroes that have long silences, such as Night Stalker and Silencer, will prevent Abaddon from saving his allies effectively and disable the active component of Borrowed Time.

* Tiny has low movespeed and attack speed, making him vulnerable to Viper's slows.
* Corrosive Skin provides magic resistance to lower Tiny's magic burst damage.

* Silencer burns easily through her effective hp from Mana Shield, by taking away her int.
* Arcane Curse punishes her repeatedly casting Mystic Snake to keep her mana pool high. Can force her to use Manta Style before he has cast Global Silence and Medusa usually does not want to build Black King Bar.

* Most of Magnus' abilities except Empower will trigger damage through Corrosive Skin.
* Poison Attack and Viper Strike can slow Magnus during Skewer, as well as putting his Blink Dagger on cooldown, preventing him from initiating or re-initiating.

* Global Silence and Last Word can prevent Ember Spirit from casting Activate Fire Remnant to escape.
* Glaives of Wisdom also provide high pure damage that is not negated by Flame Guard.
* Arcane Curse is also a potent harassing tool in the laning stage as its cooldown is lower than Flame Guard's.

* The slow applied from Corrosive Skin offsets the movement speed bonus granted by Scorched Earth and the tick-based damage from Infernal Blade and Doom will continually slow Doom down. This allows Viper, much like Sniper, to 'kite' Doom and keep him at a safe distance between the two. Additionally, Corrosive Skin applies an attack-speed slow which is fairly crippling to a hero such as Doom that, naturally, has a high base attack-time, poor agility gain and builds little attack-speed items.
* Since Doom does not disable auto-cast abilities, Viper's Poison Attack will continue to work. Doom may find it hard to close the distance between himself and Viper, and thusly difficult to effectively lockdown and continually deal damage through his abilities.

* Global Silence stops Snapfire's Mortimer Kisses.
* Last Word can prevent Snapfire from casting additional spells.

* Nethertoxin prevents the lifesteal from Ransack. The silence from Viper's level 25 talent also prevents Meepo escaping with Poof.
* Meepo and his clones have a lack of magic resistance, so they're vulnerable to Poison Attack & Viper Strike directed onto one clone.

* Nethertoxin disables Desolate and Dispersion, leaving Spectre with far less damage output and damage mitigation in engagements.
* Spectre is one of the weakest heroes at early levels. Viper can stifle her farm with early fights before Spectre purchases any major items.
Additional:
* Nethertoxin removes passives, negating Spectre's damage and survivability by removing both Dispersion and Desolate.
* Due to Haunt and Radiance's burn, Spectre is heavily susceptible to being persistently slowed and damaged by Corrosive Skin without even directly attacking Viper.
* Poison Attack and Viper Strike further slow Spectre's movement speed to a crawl, while his improved magic resistance means he can easily shrug off Radiance's burn.

* Arcane Curse punishes Grimstroke for spamming Stroke of Fate.
* Global Silence takes Grimstroke out of team fights entirely.

* Poison Attack and Viper Strike slows Axe significantly, and puts his Blink Dagger on cooldown, preventing him from initiating.
* Nethertoxin can break Counter Helix.
Additional:
* Nethertoxin prevents Counter Helix from triggering, which significantly lowers Axe's damage output in the early to mid game.
* Viper's various slows and damage over time prevents Axe from initiating as well as putting his Blink Dagger on cooldown.

* Viper's skill set makes him an effective early game ganker against Anti-Mage before he is sufficiently farmed.
* Viper's Corrosive Skin and low mana pool causes him to take little damage from Mana Void.
* Nethertoxin disables Mana Break and Counterspell, weakening both his offense and defense.

* Heroes with abilities or items that can silence or disable Anti-Mage for long periods of time will prevent him from Blinking away: Silencer, Shadow Shaman, Grimstroke, Clinkz, Riki, Faceless Void, Skywrath Mage, Puck

* Nethertoxin breaks the damage block from Bulwark.
* Poison Attack and Viper Strike's slows make it difficult for Mars to contribute to fights due to his low mobility.
Additional:
* Nethertoxin breaks Bulwark entirely, making Mars far less tanky. Using Nethertoxin inside Arena of Blood may discourage enemies from following up with Mars' initiation.
* Rod of Atos is currently common on Viper and keeps Mars in position long enough to be killed.
* Viper is not very tanky earlier in the game, so positioning against Mars is important since a well-timed Spear of Mars can be the end of Viper.

* Nethertoxin disables Vengeance Aura.
* Vengeful Spirit has no mobility spells aside from Nether Swap, which Viper can take advantage of with his slows.
* Viper can easily bully Vengeful Spirit out of a lane with Poison Attack.
Additional:
* Nethertoxin prevents attack damage bonus from Vengeance Aura and the components of Nether Swap.
* Both Magic Missile and Wave of Terror are counteracted by Corrosive Skin, making Vengeful Spirit's fighting harder against Viper.

* Shadow Demon's main source of damage is his low cooldown, high damage spells - meaning Last Word and Global Silence will pretty much take him out of the game for the duration.
* Shadow Demon likes to spam his abilities, which makes him vulnerable to Arcane Curse.
* If Shadow Demon dies near Silencer, he will lose intelligence, reducing his mana pool, mana regen and attack damage. Furthermore, if the game is long and Shadow Demon dies often, the intelligence losses will also reduce his spell damage.

* Invoker is heavily dependent on his spells, making him useless during Global Silence, as well as interrupting Invoker during his combo.
* Arcane Curse is particularly deadly, because Invoker will continuously lose health if he keeps invoking and casting new spells.
* Last Word will silence Invoker when he casts Invoke, interrupting his combo.

* Corrosive Skin makes Viper receive less damage from Invoker's spells
* Viper can harass Invoker with his Poison Attack in the early game.
* Viper Strike and Poison Attack can kill Invoker easily if Ghost Walk is on cooldown.

* A well-timed Global Silence prevents Dazzle from saving allies with Shallow Grave or Shadow Wave. Items that could dispel the silence are expensive, and difficult for Dazzle to farm from a support role.
* Arcane Curse and Last Word cause long damage over time, which may outlast Shallow Grave.

* As Tinker relies heavily on his spells to be effective, Last Word and Global Silence will render him largely useless.
* Arcane Curse effectively prevents Tinker from casting spells during its duration, as he will otherwise suffer heavy damage.
* Glaives of Wisdom deal pure damage, which make quick work of fragile heroes like Tinker.
Additional:
* Silencer can stop Rearm, preventing Tinker from spamming his abilities/items or escaping.

* Arcane Curse can effectively discourage Undying from casting his spammable abilities in a team fight, as Undying will have to suffer more damage and the slow due to the penalty duration of Arcane Curse.
* Last Word and Global Silence are able to silence Undying for up to 6 seconds, preventing Undying from gaining strength and healing his ally or himself.

* Corrosive Skin means Viper can often outlast Venomancer in a battle of attrition.
* Venomancer has no mobility without items, which makes him vulnerable to constant slows.

* Nethertoxin breaks Multicast.
* Corrosive Skin minimizes the damage during Ignite and Fireblast.

* Silencer's Last Word and Global Silence prevents Jakiro from casting any spell.
* A carry Silencer can easily take down a support Jakiro with his Glaives of Wisdom.

* Nethertoxin cancels out Kraken Shell and stops the hard dispel from passively activating, preventing Tidehunter from functioning as a frontline tank.
* Anchor Smash is mostly irrelevant against a ranged hero.
* Tidehunter relies on the threat of Ravage, which has an obscenely long cooldown. Viper can exploit the downtime with his short cooldowns.

* Both Arcane Curse and Last Word punishes casters with spammable spells such as Sand King.
* As a strength caster, Intelligence Steal reduces Sand King's mana pool even more.
* Global Silence silences Sand King, effectively reducing Sand King's initiation and counter-initiation potential. It can also interrupt channeling of Epicenter.

* Last Word and Arcane Curse have the range to hit Dark Willow beyond Bramble Maze.
* Global Silence renders Dark Willow useless in teamfights.

* Poison Attack makes it hard for Void Spirit to lane against him.
* Corrosive Skin reduces the magical damage from Void Spirit's spells.

* His Poison Attack is very useful against Huskar, since he tends to stay at low health.
* Nethertoxin disables passive skills like Berserker's Blood.
* It is dangerous for Huskar to jump on Viper because Corrosive Skin and Viper Strike with the slowdown of movement and attack speed which usually will be deadly for Huskar.
Additional:
* Nethertoxin disables Berserker's Blood, which Huskar relies upon for attack speed and healing.
* The damage from Burning Spear and Life Break is largely absorbed by Corrosive Skin. It also will return some damage, making it risky to use Burning Spears in the laning stage.
* Because Huskar wants to be on low health for Berserker's Blood, he is particularly vulnerable to Poison Attack.

* Heroes with pure damage can kill Huskar when he inevitably gets low on health: Outworld Destroyer, Silencer.

* Nethertoxin cuts off Gravekeeper's Cloak, Visage's primary defense mechanism.
* Viper can ignore Grave Chill's attack speed slow with his magic damage output.
Additional:
* Since Visage is a slow hero, Viper can easily kite him with Poison Attack and Viper Strike while successfully chipping away at Gravekeeper's Cloak.
* Nethertoxin removes all layers of Gravekeeper's Cloak, leaving Visage exposed.
* Corrosive Skin makes Viper highly resistant to Soul Assumption.

* Generally strong against every spellcaster, Puck fully relies on their skill set and is barely a threat when silenced.
* Arcane Curse disables Blink Dagger for quite some time, and is also effective against Puck as he tend to use his spells a lot.
* Glaives of Wisdom can do a lot of damage against Puck due to Puck's low agility gain and armor.
* Last Word can prevent Puck from getting his full combo off, limiting his effectiveness in team fights or ganks.
* Global Silence can take Puck out of fights entirely.

* Silencer's intelligence steal will heavily reduce Outworld Destroyer's damage output, if Outworld Destroyer dies a lot near/to Silencer.
* Global Silence and Last Words will render Outworld Destroyer helpless unless he has dispelling item/ally.
Additional:
* Silencer's Intelligence Steal will heavily reduce Outworld Devourer's damage output, particularly from Sanity's Eclipse.
* Last Word and Global Silence will take Outworld Devourer out of the fight unless he has built Black King Bar.

* Viper's poison abilities can slow Bounty Hunter's movement speed and allows to chase him with True Sight items.
* Nethertoxin can break Jinada, and the silence from level 25 prevents Bounty Hunter from using all of his spells.

* Viper's Poison Attack and Viper Strike that can slow Razor, and is one of the few heroes that can keep him immobile.
* Altogether, Viper's skills reduce Razor's attack speed, heavily reducing the benefit of the damage drain from Static Link.
Additional:
* Storm Surge is counteracted by Nethertoxin, leaving Razor without faster MS.
* Static Link's damage drain doesn't bother Viper a lot as most of his early to mid game damage is magical.

* Heroes with break can disable Untouchable for a while: Doom and Shadow Demon (via Aghanim's Scepter), Viper

* Melee heroes with low mobility can be kited and killed by Viper: Treant Protector, Kunkka, Alchemist, Troll Warlord, Wraith King, Tiny, Sven.

* Heroes with silencing abilities that are not blocked by Linken's Sphere, like Puck's Waning Rift, Death Prophet's Silence or Silencer's Global Silence.

* Hand of God has a long cooldown, so damage over time spells can be hazardous for Chen, forcing him to use it prematurely: Jakiro, Venomancer, Viper, Dazzle, Phoenix.

* Heroes with silencing abilities can be particularly deadly when Slark is trying to escape: Silencer, Death Prophet, Puck, Doom

* Nethertoxin negates Essence Shift and the regeneration aspect of Shadow Dance.
* Dark Pact doesn't mean a lot against Viper's ubiquitous slows.
* Viper becomes a relevant presence in team fights before Slark can procure his standard items (e.g. Shadow Blade).

* Basically, Heroes that heavily rely on abilities for damage or escape, such as Queen of Pain and Storm Spirit.

* In general, heroes such as Lion, Silencer, Skywrath Mage, Sven, Ogre Magi and others with reliable disables are crucial to killing Techies before they can suicide.

* Heroes with silence such as Riki, Silencer, or Night Stalker prevents Skywrath Mage from using his spells.

* Heroes that can slow Charge of Darkness by a huge amount: Venomancer, Viper, Dazzle, Arc Warden

* Melee heroes with low mobility can be kited and killed by Viper: Treant Protector, Kunkka, Alchemist, Troll Warlord, Wraith King, Tiny, Sven.

* Heroes with silences and hard stuns such as Doom, Silencer, and Lion can keep Mirana from Leaping away.

* Melee heroes with low mobility can be kited and killed by Viper: Treant Protector, Kunkka, Alchemist, Troll Warlord, Wraith King, Tiny, Sven.

* Viper can bully Alchemist out of mid lane quite easily, forcing him to either retreat into jungle, or stay harassed in lane, and get very few last hits. Vipers break also completely disables Greevil's greed which prevents Alchemist to earn his amazing amounts of money.

* Viper's Nethertoxin disables Cloak and Dagger, negating Riki's invisibility and much of his damage. It also makes him more vulnerable to magic damage, which does not go well with Riki's low health pool. With the talent applied, he can't even blink to safety or hide with Tricks of the Trade.
* Corrosive Skin makes it hard for Riki to chase Viper and attack him due to the attack speed slow.
* Viper Strike stays on Riki even after he goes invisible.
* Poison Attack makes it risky for Riki to get last hits and can make the laning phase difficult for him.

* The damage over time from Viper's Poison Attack and Viper Strike rapidly wear down Refraction charges, allowing Templar Assassin to be damaged. Additionally, Corrosive Skin causes her attacks to apply damage over time on her as well.
* Nethertoxin is a big threat to Templar Assassin. Her initially low range making it very hard to deal against Nethertoxin in laning phase. At any stage of the game, a Nethertoxin can always force her to undo her Meld.
Additional:
* All of Viper's abilities quickly burn through Refraction charges.
* Templar Assassin's short range, aside from Psi Blades' spill damage, makes her vulnerable to Poison Attack harassment.
* Templar Assassin traditionally forgoes health and armor items for damage. Outside of Black King Bar, Viper will almost always be able to kill her when Refraction is down.

* Because Warlock's abilities are all active abilities, Silencer can make his impact minimal.
* Arcane Curse prevents Warlock from using his abilities without taking 56/84/112/140 damage, and slowed by 9%/12%/15%/18%.
* Last Word can prevent Warlock from casting his combo.
* Global Silence can nullify Warlock's impact in fights and prevent him from getting any spells off.

* Silencer can easily ruin Enigma's initiation, as Global Silence cancels Black Hole, even through Black King Bar and Linken's Sphere.
Additional:
* Last Word can be cast from a long range to prevent Enigma's potential initiation.
* Global Silence can interrupt Enigma's Black Hole channeling through Black King Bar and Linken's Sphere.

* Since Windranger is bad against magical damage, heroes with continuous magical damage or magical nukes can blast her: Zeus, Tinker, Leshrac, Viper, Skywrath Mage, Lion, Lina, Venomancer.

* Windranger heavily relies on her abilities for any form of tactical advantage and damage. A well timed silence will make her useless: Puck,Silencer, Death Prophet, Skywrath Mage, Drow Ranger, Earth Spirit, Grimstroke.

Additional:
* Silencer's abilities hamper Windranger's effectiveness in battle, preventing her from comboing abilities and escaping using Windrun.

* Nethertoxin breaks both Necromastery and Presence of the Dark Lord, reducing his damage massively.
* Corrosive Skin gives Viper bonus Magic Resistance against Shadowraze and Requiem of Souls.
* Viper can easily take advantage of Shadow Fiend's lack of escape and mobility spells with Viper Strike and Poison Attack. Poison Attack also serves as a great way to harass Shadow Fiend.

* Like any hero with a channeled spell, Last Word is a counter to it.
* Global Silence goes through spell immunity and prevents Witch Doctor from casting his spells.

* While many of Silencer's spells are a great steal for Rubick, Silencer effectively neuters Rubick's excellent counter-initiation potential thanks to Global Silence.
* Rubick's relatively low intelligence for such a heavy caster means that losing Intelligence to Intelligence Steal will make your mana pool even smaller.

* Nethertoxin breaks Sniper's passives.
* Viper Strike together with Poison Attack can slow Sniper and tears through his low health and mobility.

* In the early game, a Dragon Knight without Black King Bar is basically defenseless against Viper.
Additional:
* Dragon Knight is easily harassed by Poison Attack after the laning stage ends.
* Corrosive Skin protects Viper from Breathe Fire and returns damage.
* Nethertoxin mitigates Dragon Blood, Dragon's Knight main source of armor and health regeneration.
* Between Poison Attack and Viper Strike, Viper can keep Dragon Knight permanently slowed even in Elder Dragon Form.

* Silencer's Intelligence Steal can reduce Storm Spirit's damage output if he gets some kills on laning phase.
* Last Word and Global Silence will make Storm Spirit an easy target.
* Global Silence can be used to block Storm Spirit from connecting abilities after a Ball Lightning on his targets.

* Oracle's reliance on spamming his spells can be easily hindered by Silencer's Arcane Curse.
* Last Word and Global Silence negates Oracle's attempt to save his allies with his spells.
* Fate's Edict is useless against Glaives of Wisdom's pure damage.

* Lion is extremely dependent on his abilities. Silences like Silencer's Last Word, magic resistance like Oracle's Fate's Edict, and dispels like Legion Commander's Press the Attack all make his abilities less effective.

* Nethertoxin breaks Fury Swipes, making Viper a decent counter to Ursa in a laning stage.
* Viper Strike is a strong, undispellable slow, making it much easier to kite Ursa for everyone.

* Nethertoxin prevents the buildup of Jingu Mastery stacks.
* Viper's poison magical damage-over-time stops Monkey King from using Tree Dance. It also ignores the extra armor bestowed by Wukong's Command.
Additional:
* Nethertoxin prevents the buildup of Jingu Mastery stacks.
* Monkey King's high base movement speed is of little worth against the array of slows Viper possesses.
* All of Viper's magical damage over time stops Monkey King from using Tree Dance. It also ignores the extra armor bestowed by Wukong's Command.

* With 4 active abilities, Shadow Shaman is weak against silencing foes such as silencer, Drow Ranger and Death Prophet.

* Pugna is very reliant on his abilities for damage. (Just be careful around the Nether Ward)

* Corrosive Skin minimizes the damage from Impale and Mana Burn.
* Nyx Assassin cannot survive several poison damage-over-time, even Spiked Carapace is activated.
* However the Vendetta break can be dangerous for Viper.