* Pugna is a very fragile hero who can easily get caught and killed by Storm Spirit's long range initiation.
* This is especially true if he has Orchid Malevolence or Scythe of Vyse.
* Pugna has no disables that can prevent Storm Spirit from escaping.
* Even though Ball Lightning requires high amount of mana, Nether Ward is ineffective since Storm Spirit is invulnerable while using it.
* Storm Spirit's other abilities cost very insignificant amount of mana for Nether Ward to be effective.

* 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 AoE abilities are a bane to Beastmaster's summons: Storm Spirit, Magnus, Pangolier.

* Heroes with escape abilities: Anti-Mage Dark Seer Slark Storm Spirit Windranger Weaver can kite Lifestealer due to him having no lockdown.

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

* Heroes with teleports to escape Solar Blind and Will-O-Wisp: Phantom Assassin, Puck, Queen of Pain, Storm Spirit

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

* Escape-type carries: Slark, Storm Spirit, Weaver.

* Heroes that rely on their high mobility such as Queen of Pain, Slark and Weaver can be constantly engaged against due to your excellent ability to chase over any terrain. Make sure you carry true sight items (such as Dust of Appearance or Gem of True Sight) for invisible heroes that could potentially escape your clutches.

* Heroes with Attack speed decreasing skills: Jakiro, Viper Lich

* Ball Lightning allows Storm Spirit to easily catch up to Monkey King, destroying a large number of trees, cancelling Tree Dance, and causing Monkey King to be stunned in the process.
Additional:
* Ball Lightning allows Storm Spirit to destroy a large amount of trees, negating Tree Dance. It also makes it easy to avoid Wukong's Command and Boundless Strike.

* 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:
* Viper STrike 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.

* Storm Spirit can close the distance towards Sniper very easily with his ultimate Ball Lightning.
Additional:
* Sniper is very squishy and cannot deal with heroes that jump onto him and lock him down. Storm Spirit closes the gap in a fight against Sniper, and Sniper has no way to escape except for some items.
* Storm Spirit can dodge Assassinate with a correctly timed Ball Lightning.

* Viper Strike breaks Sniper's passives.
* Corrosive Skin allows Viper to deal more damage to Sniper than Sniper deals to him when laning, especially by briefly stepping into Shrapnel.
* Nethertoxin together with Poison Attack can slow Sniper and tears through his low health and mobility.

* Ball Lightning makes Storm Spirit a target difficult to chase, even for a hero as mobile as Timbersaw.
* The magical damage from Static Remnant and Overload together with Storm Spirit's high mobility allows Storm Spirit to jump on Timbersaw and burst him down, even if he tries to escape.

* Viper Strike prevents Timbersaw from gaining stacks on Reactive Armor.

* Ball Lightning makes it almost impossible to catch Storm Spirit without someone else initiating for you.
* Overload is not reduced by Bulwark and the magical damage spam can wear down Mars quickly.
Additional:
* Storm Spirit's abilities all do magical damage, which can bypass Bulwark.
* Ball Lightning can escape through Arena of Blood and it is easy to dodge Spear of Mars.

* 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:
* Viper Strike can disable Bulwark entirely, making Mars far less tanky. Using Nethertoxin inside Arena of Blood may discourage enemies from following up with Mars's initiation.
* Rod of Atos is currently common on Viper and keeps Mars in position long enough to be killed.
* However, Viper is not very tanky earlier in the game, so positioning against Mars is important for Viper since a well-timed Spear of Mars can be the end of Viper.

* Storm Spirit can steal Aegis of the Immortal during Roshan attempts through the Pit, because of his Ball Lightning.
* Ursa has no way to catch a slippery Storm Spirit, as Earthshock's slow will do nothing to stop Storm Spirit from using Ball Lightning.

* Viper Strike is a strong and breaks Fury Swipes, undispellable slow, making it much easier to kite Ursa for everyone.

* Storm Spirit can exploit every one of Spectre's weaknesses, and thus is one of the best counters against her.
* Spectre has to be in melee range to deal damage, making her likely to trigger Static Remnants and susceptible to being kited by Overload procs.
* Electric Vortex can lock Spectre down as she doesn't like to build Black King Bar.
* Ball Lightning gives Storm Spirit multiple advantages:
* Spectre cannot evade Storm Spirit, as Ball Lightning is superior to Spectral Dagger in terms of mobility.
* Storm Spirit can kite her and her Haunt illusions when it's later in the game due to her having no form of pseudo-blinks (Reality is far inferior to Ball Lightning).
* It is very difficult for Spectre to deal any substantial damage against Storm Spirit with Desolate. Ball Lightning grants invulnerability and can mitigate damage done from Dispersion and Radiance.
* To mitigate this, Spectre needs a team with hard disable to take Storm Spirit out.
Additional:
* Ball Lightning is the ultimate counter to Spectre's entire toolkit. With this ability, he can score easy kills on Spectre without her having any means of escape early game, kite her and her Haunt illusions when it's later in the game due to her having no form of pseudo-blinks.
* Furthermore, it is very difficult for Spectre to deal any substantial damage against Storm Spirit with Desolate, and without both Manta Style and Diffusal Blade he will always remain on the move.
* Also, Ball Lightning grants invulnerability, and as Storm Spirit likes to spam that ability, he can mitigate the damage done from Dispersion and Radiance.

* Nethertoxin disable 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.
Additional:
* Viper Strike can disable 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.

* Ball Lightning disjoints an incoming Magic Missile, avoids Wave Of Terror, and allows Storm Spirit to easily escape if he ever gets Nether Swapped.

* 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:
* Viper Strike can disable the 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.

* Any hero with teleport abilities (e.g. Ember Spirit, Storm Spirit) can easily break Static Link.

Additional:
* Ball Lightning breaks Static Link.
* Razor has no way to catch a slippery Storm Spirit.

* 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 Viper Strike, leaving Razor without his extra movement speed.
* Static Link's damage drain doesn't bother Viper a lot as most of his early to mid game damage is magical.

* Squishy heroes or heroes without hard disables or silences: Shadow Demon, Shadow Fiend, Venomancer, Ancient Apparition etc.

* Nethertoxin 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 breaks and Poison Attack. Poison Attack also serves as a great way to harass Shadow Fiend.

* Squishy heroes or heroes without hard disables or silences: Shadow Demon, Shadow Fiend, Venomancer, Ancient Apparition etc.

* 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.

* Heroes with invisibility and high mobility can jump on and focus down Earthshaker before he has a chance to initiate: Clinkz, Slark, Storm Spirit

* 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.
* Viper Strike can disable Aftershock, which removes the stun and bonus damage from Enchant Totem and Echo Slam.

* Zeus can deal a huge amount of damage, but he lacks defensive abilities, such as good mobility or resistance. Due to that, he doesn't like to be touched by any means. Heroes with higher damage output and good mobility will often get easily near Zeus and trade damage (eventually causing Zeus's downfall). Such Heroes include: Lycan, Slark, Storm Spirit, Spectre and others.

* 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.
Additional:
* 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.

* Heroes with mobility/escape mechanisms to dodge Ancient Apparition abilites, or to easily jump on him: Riki, Queen of Pain, Phantom Assassin, Windranger, Bounty Hunter, Spirit Breaker, Night Stalker, Storm Spirit, Juggernaut, etc.

Additional:
* Ancient Apparition's only skill to stop Storm Spirit is Cold Feet, which is bad in general when trying to stop a Storm Spirit without any other disable.
* As a fragile support with low Strength gain and no magic resistance, Ancient Apparition is vulnerable to Storm Spirit's combos.

* 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.

* Heroes that are naturally hard to gank, ranging from beefy tanks like Abaddon and Wraith King to heroes with quick escape mechanisms like Anti-Mage and Storm Spirit are also undesirable targets for a lone, roaming Bounty Hunter to scout out and initiate on.

* 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.

* Heroes that can easily bypass Chen's creeps to get to Chen: Riki, Tusk, Clinkz, Sniper, Slark, Phantom Assassin, Void Spirit, Storm Spirit, Ember Spirit, Earth Spirit, Spirit Breaker.

* 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 that usually build Linken's Sphere as either a core or situational item: Weaver, Medusa, Morphling, Queen of Pain, Storm Spirit, Luna, Naga Siren.

* Heroes that can slow Charge of Darkness by a huge amount: Venomancer, Viper, Dazzle, Arc Warden, Lion, Huskar, Shadow Shaman, Visage, Undying, Jakiro.

* Storm Spirit can easily make his way to Hoodwink with his ultimate Ball lightning, and coupled with Hoodwink's low health and magic resistance, she can be nuked easily.
* Additionally, Ball lightning can destroy a small amount of trees in its destination. Combined with Storm Spirit's frequent usage of his ultimate, he can clear out an area of trees while simultaneously attacking him and dodging incoming attacks.

* 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 overtime 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 the 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 usually buys health and armor items for damage. Outside of Black King Bar, Viper will almost always be able to kill her when Refraction is down.

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

* In the early game, a Dragon Knight without Black King Bar is basically defenseless against Viper.
* Viper can harass Dragon Knight at any time with his Poison Attack and Nethertoxin.
* Corrosive Skin reduces damage from Dragon Fire and inflicts damage to him.
* Viper Strike disables Dragon Blood, negating his main survivability.
* Viper Strike and Poison Attack can severely slow him down even with his Elder Dragon Form.
Additional:
* Dragon Knight is easily harassed by Poison Attack after the laning stage ends.
* Corrosive Skin protects Viper from Breathe Fire and returns damage.
* Viper Strike can disable 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.

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

* Ball Lightning allows Storm Spirit to bypass Bramble Maze into the backline, and zip back into battle if he gets hit by Terrorize.

* Shadow Demon will have a hard time catching Storm Spirit, as he can get away with Ball Lightning.
* Static Remnant will make quick work of the spawned illusions from Disruption.
* With very high mobility and usually being paired with Orchid Malevolence, he can catch Shadow Demon with ease both in ganks and in teamfights if Shadow Demon has no survivability items.

* Storm Spirit can quickly close the distance with Lina using Ball Lightning. In addition, Ball Lightning can be used as a way to dodge the abilities of Dragon Slave and Light Strike Array
Additional:
* Storm Spirit can quickly close the distance with Lina using Ball Lightning. In addition, Ball Lightning can be used as a way to dodge the abilities of Dragon Slave and Light Strike Array

* Viper Strike prevents buildup of Fiery Soul stacks.
* Corrosive Skin provides magic resistance against Lina's spells. However, Lina can counter this with Silver Edge, a common item on Lina.
* Poison Attack and Viper Strike can burn away Lina's small health pool.

* 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:
* Viper Strike can disable 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.

* Storm Spirit outlanes Earth Spirit wins by having a ranged attack type, and also deals damage to the Earth Spirit every time he approaches the creeps with his ability Static Remnant, which is why he overtakes Earth Spirit in level and gold
* Storm Spirit has the ability to quickly kill Earth Spirit under his ability Electric Vortex, which Earth Spirit cannot do if Storm Spirit buys Falcon Blade at the liner stage, because Storm Spirit will have too much health for Earth Spirit`s abilities and will survive Earth Spirit`s damage.
Additional:
* Storm Spirit outlanes Earth Spirit wins by having a ranged attack type, and also deals damage to the Earth Spirit every time he approaches the creeps with his ability Static Remnant, which is why he overtakes Earth Spirit in level and gold
* Storm Spirit has the ability to quickly kill Earth Spirit under his ability Electric Vortex, which Earth Spirit cannot do if Storm Spirit buys Falcon Blade at the liner stage, because Storm Spirit will have too much health for Earth Spirit`s abilities and will survive Earth Spirit`s damage.

* Viper Strike breaks Multicast.
* Corrosive Skin minimizes the damage from Ignite and Fireblast.

* Storm Spirit is invulnerable during Ball Lightning, allowing him to zip away from any ganking attempts with Rupture.
* Ball Lightning also prevents Bloodseeker from chasing down an injured Storm Spirit, or catching him in Blood Rite.
Additional:
* Storm Spirit is invulnerable during Ball Lightning, rendering Rupture ineffective against him.

* 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.

* Viper STrike 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 like Viper.
* Tidehunter relies on the threat of Ravage, which has an obscenely long cooldown. Viper can exploit the downtime with his short cooldowns.

* Nethertoxin disables Dawnbreaker's Luminosity. Since she's a melee hero, she needs to close gap to attack and Nethertoxin will be bad for her since she cannot heal.
* Viper Strike and Poison Attack will severely slow her down and combined with Nethertoxin, it will be her death sentence (unless her Celestial Hammer or Solar Guardian are off cooldown). Besides that, chasing her down will be easy due to the slow.

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

* Poison Attack and Viper Strike slows Axe significantly, and puts his Blink Dagger on cooldown, preventing him from initiating. Viper Strike can also break from Counter Helix.
Additional:
* Viper Strike 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 Strike can disable 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.

* Because Poison Attack has almost no cooldown, Aphotic Shield is ineffective as a hard dispel.
* Viper Strike can prevent Borrowed Time from activating passively and block Curse of Avernus.
Additional:
* Because Poison Attack has almost no cooldown, Aphotic Shield is ineffective as a hard dispel.
* Viper Strike can prevent Borrowed Time from activating passively and block Curse of Avernus.

* Ball Lightning can escape quickly fear from Focus Fire. Windranger can not reach Storm Spirit although Windrun active catch him.
Additional:
* The high mobility provided by Ball Lightning makes it hard for Windranger to find a good position to land Shackleshot or a full duration of Focus Fire. It can be also used to dodge Powershot.

* 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.

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

* Heroes that have superior mobility that can easily catch up with Mirana even after she used Leap to escape: Anti-Mage, Queen of Pain, Storm Spirit, Riki.

* Heroes with abilities that can close the gap can easily kill Muerta: Storm Spirit, Earth Spirit, Ember Spirit, Void Spirit, Lycan, Chaos Knight, Tusk.

* Heroes with high mobility will be able to avoid Gyrocopter's area attacks: Storm Spirit, Morphling, Ember Spirit

* Heroes with mobility spells can quickly escape from Stroke of Fate or break out of Soulbind: Anti-Mage, Queen of Pain, Morphling, Storm Spirit

* Heroes with considerable mobility can easily escape from a rolling Pangolier: Anti-Mage, Queen of Pain, Void Spirit, Storm Spirit, Ember Spirit, Earth Spirit, moreover, if a player is familiar with how Rolling Thunder works, they can adjust their movement to avoid it entirely and of course outplay the Pangolier player.

* Any hero who can survive Magnus's initiations and manfight him: Huskar, Faceless Void, Weaver, Abaddon, Troll Warlord, Alchemist, Dragon Knight, Night Stalker, Viper.

Additional:
* Most of Magnus's 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.

* 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.

* Heroes that can apply early pressure before Phantom Assassin has farm are massive threats: Axe, Viper, Meepo, Jakiro, Pugna, Slark, Venomancer etc.

* 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.

* Heroes that can reliably kite out Dispose, Unleash and dodge Rebound, like Ember Spirit, Void Spirit, Storm Spirit, Anti-Mage, Faceless Void, Puck or always build items like Blink Dagger and Force Staff.

* Heroes that can easily bypass Io's allies to get to Io: Riki, Tusk, Clinkz, Sniper, Slark, Phantom Assassin, Void Spirit, Storm Spirit, Ember Spirit, Earth Spirit, Spirit Breaker, Lifestealer.

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

* Heroes with escaping and disjointing abilities can be good against Juggernaut:Anti-Mage Riki, Queen of Pain, Puck, Storm Spirit, Ember Spirit, Slark etc.

* Ball Lightning can be used to clear Nature's Prophet's Treants and easily destroys Sprout.
* Electric Vortex prevents Nature's Prophet's escaping using Teleportation.

* Viper wins on the central line of Puck, because he has a huge damage from the Poison Attack ability, which Puck is not able to constantly avoid using Phase Shift, which will give Viper an advantage in the possible damage inflicted on each other
* Puck takes more damage than it does due to the passive Corrosive Skin ability of the Viper, which makes it unprofitable for the Puck to fight against the Viper at an early stage of the game, when the Puck has a very small pool of health.
Additional:
* Viper wins on the central line of Puck, because he has a huge damage from the Poison Attack ability, which Puck is not able to constantly avoid using Phase Shift, which will give Viper an advantage in the possible damage inflicted on each other
* Puck takes more damage than it does due to the passive Corrosive Skin ability of the Viper, which makes it unprofitable for the Puck to fight against the Viper at an early stage of the game, when the Puck has a very small pool of health

* In the early to mid game, Invoker is defenseless against Storm Spirit's ganking with Ball Lightning and Orchid Malevolence.

* 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.

* Viper does large amounts of magic damage over time, meaning that if a Necrophos uses Ghost Shroud, Viper's abilities will greatly reduce Necrophos survivability, and may actually kill him.
* By the same token, Viper can use his Viper Strike on Necrophos if he attempts to heal himself with Ghost Shroud, and depending on any other effects Necrophos may have from him, (IE:Poison Attack,Corrosive Skin), Viper can often kill Necrophos while he is in his Ghost Shroud.
* Viper's Corrosive Skin helps him take reduced damage from all of Necrophos spells that deal magical damage, which is his only source of damage.
Additional:
* Viper Strike 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.

* Storm Spirit can hunt down Arc Warden with his Ball Lightning and kill him quickly due to his lack of escape abilities.
* None of his abilities are effective against Storm Spirit, as they can be evaded with Ball Lightning.

* An isolated Enigma in the early game can be easily killed by Storm Spirit thanks his higher mobility and dueling potential. However, Storm Spirit can be killed when caught by Enigma's full combo, especially if Enigma has Black King Bar.
* Storm can kill all of Enigma's Eidolons relatively quickly without much risk, slowing down Enigma's farming speed, preventing him from split pushing, and giving Storm its considerable bounty, especially if Enigma chooses the Level 25 Talent that gives him more Eidelons.
* Storm can zip through Black Hole stunning Enigma while he's channelling until Enigma buys Black King Bar.

* Heroes that rely on their high mobility such as Queen of Pain, Slark and Weaver can be constantly engaged against due to your excellent ability to chase over any terrain. Make sure you carry true sight items (such as Dust of Appearance or Gem of True Sight) for invisible heroes that could potentially escape your clutches.

* Heroes with Break abilities will prevent Slark from regenerating and gaining Essence Shift stacks: Viper, Shadow Demon, etc.

Additional:
* Viper Strike can disable 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).

* Corrosive Skin will protect Viper from Techies' magical damage.
* Even though Reactive Tazer will disarm Viper if he attacks Techies with Poison Attack, he does lots of damage with his other abilities that can still kill Techies.

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

* 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.

* Storm Spirit has multiple AoE abilities to deal with Phantom Lancer, especially with Aghanim's Scepter.
* Ball Lightning destroys illusions, avoids Spirit Lance, and makes Storm Spirit very hard to catch, even with Phantom Rush.
Additional:
* Ball Lightning with or without the Static Remnant talent allows Storm Spirit to destroy Phantom Lancer's illusions quickly. It is also easy to dodge Spirit Lance with Ball Lightning and makes Spirit Storm very hard to catch even with Phantom Rush.

* Ball Lightning allows Storm Spirit to close the gap between him and Weaver in no time. Once locked down with certain items, Weaver is extremely fragile to Storm Spirit and his teammates.

* Terrorblade has low mobility, which makes it easy for Storm Spirit to kite him.
* Terrorblade gains a lot of agility and gains very low strength, which makes it easy to burst him down with Storm's magical damage.
* All of Terrorblade's abilities are easily avoided by Storm Spirit as he can simply use Ball Lightning, wasting the duration of Metamorphosis, Conjure Image, and Reflection.
* However, if Storm Spirit's Orchid Malevolence is on cooldown or if he doesn't have it, Terrorblade can easily use Sunder and kill a careless Storm Spirit.
Additional:
* Storm Spirit has heavy magic damage that bypasses Terroblade's high armor.
* Ball Lightning can either use to initiates Terroblade from distance or kite Terroblade from using Sunder as he has no source of disable to deal with Storm Spirit outside of Terror Wave from Aghanim's Scepter.

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

* Storm Spirit is not only a potent Orchid Malevolence carrier, his Electric Vortex provides an additional disable and Overload provides a great slow. When paired with Static Remnant, they can cut through Flame Guard fast.
* Ball Lightning not only provides great initiation upon Ember Spirit from any position anytime, but also helps dodge Sleight of Fist.

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

* 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.

* Storm Spirit destroys trees and ignores impassable terrains with Ball Lightning, rendering them dangerous places for Tinker to hide within.
* Ball Lightning disjoints projectile from Heat-Seeking Missile and damage from March of the Machines.
* Electric Vortex prevents Tinker from teleporting away, and Static Remnant and Overload can easily burst him down.
Additional:
* He can easily catch Tinker in the trees with Ball Lightning and kill him with Orchid Malevolence and his abilities, which deal both physical and magical damage, making them difficult for Tinker to itemize against.

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

* Corrosive Skin minimizes the damage from Impale and Mind Flare, and anything else Nyx Assassin tries to throw at Viper.
* Nyx Assassin cannot survive several poison damage-over-time output from Poison Attack, Nethertoxin, Corrosive Skin and Viper Strike, not even while he has Spiked Carapace active. And to make things worse, Nyx Assassin is not a common Silver Edge wielder to counter this problem at all.
Additional:
* Corrosive Skin minimizes the damage from Impale and Mind Flare, and anything else Nyx Assassin tries to throw at Viper.
* Nyx Assassin cannot survive several poison damage-over-time output from Poison Attack, Nethertoxin, Corrosive Skin and Viper Strike, not even while he has Spiked Carapace active. And to make things worse, Nyx Assassin is not a common Silver Edge wielder to counter this problem at all.

* Viper Strike prevents the lifesteal from Ransack.
* Meepo and his clones have a lack of magic resistance, so they're vulnerable to Poison Attack & Viper Strike directed onto one clone.

* Heroes with damage-increasing passive abilities, such as Viper and Riki, will usually kill Silencer in a short time before he even has time to set up his abilities.

* Ball Lightning and Electric Vortex will catch Broodmother before she has a chance to retreat, and is able to catch her through the trees.
* Conversely, Ball Lightning also allows him to easily escape Broodmother, as she has no way to prevent him from using it before getting Orchid Malevolence.