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

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

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

* Durable heroes can stand against Tusk during 1v1: Axe, Dragon Knight, Night Stalker, Centaur Warrunner, Wraith King and more.

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

* 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.

* 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.

* Dark Ascension also allows Night Stalker to fly over Proximity Mines without triggering them.
* Crippling Fear is effective in stopping Techies from using Blast Off and Void is effective in stopping them from running to the safety of their mines.

* 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.

* Void can be used to cancel Requiem of Souls.
* Crippling Fear prevents Shadow Fiend from using Shadowraze or Requiem of Souls.
* With Dark Ascension and Gem of True Sight, Night Stalker can find and kill Shadow Fiend easily. He is also a tanky hero that can fight Shadow Fiend at any stage of the game.

* 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

* Puck cannot use any of its normal means to survive should Night Stalker catch it within Crippling Fear, and goes down quickly.
Additional:
* Void is a potent nuke that is devastating to Puck's low health pool.
* Crippling Fear silence can prevent Puck from casting spells, leaving it vulnerable.

* 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.

* With Dark Ascension and Gem of True Sight, Night Stalker can easily find and kill Riki. Riki will also find it harder to kill the tanky Night Stalker than he would many other heroes.

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

* May effortlessly get to and take down Disruptor.
* Void deals heavy single target damage and slow. Lacking innate escape mechanisms justs puts Disruptor in trouble
* Crippling Fear silences, and Disruptor is extremely dependant on abilities to work and to fend for himself.
* Hunter in the Night provides Night Stalker movement speed, attack speed and strengthens his abilities during night time, allowing him to easily catch up and obliterate Disruptor
* With Black King Bar, it's mostly assured to target down Disruptor.

* 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.

* Crippling Fear makes it so Axe might use Blink Dagger right into an AoE silence in the middle of everyone.
* Void cripples Axe's already bad movement speed and attack speed.
* Hunter in the Night makes it impossible for Axe to catch up to fleeing or escape from Night Stalker during the night.
* Lastly, Dark Ascension gives full vision over Axe before he initiates, making the opponents all recognize his location immediately and allowing Night Stalker to prevent it or vocally tell his team if needed.
* Night Stalker has very high strength gain, even in the lane, so a successful Culling Blade is very unlikely.
* Axe's Blade Mail will likely do nothing to Night Stalker because of his high health and certain requirements for him to do the most damage to be true.

* 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).

* With Dark Ascension he can keep vision on Slark, disabling his Shadow Dance regeneration.
* Night Stalker is very fast so without the Pounce in lane, he can simply out distance him during the night.
* Slark is matched in night vision by only a few heroes, Night Stalker happens to be one of them.

* 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.

* Dark Ascension reduces vision for the enemy team, which makes it more difficult for Magnus to initiate with Blink Dagger and Reverse Polarity. It is also more likely that Night Stalker will scout out Magnus with Aghanim's Scepter and a Gem of True Sight, after which he can silence Magnus with Crippling Fear.

* 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.

* Earthshaker must be careful not to use Blink Dagger or Aghanim's Scepter upgraded Enchant Totem to blink into Riki's Smoke Screen or Night Stalker's Crippling Fear, as these field effects will instantly silence Earthshaker and prevent him from initiating.

Additional:
* Fissure has a short stun and creates an impassable ridge. However, Night Stalker can fly over it during Dark Ascension.
* Night Stalker can find Earthshaker, disable his Blink Dagger with Void, and then take him out with Crippling Fear.
* Earthshaker may fail his blink combo against Night Stalker's team if he is not careful, as he can blink into the silence.

* 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 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.

* 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.

* Heroes that have a weak laning stage: Spectre, Nyx Assassin, Clockwerk, Spirit Breaker, Omniknight, Pudge.

* 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 low mobility that rely on spells: Zeus, Lina, Crystal Maiden.

* 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.

* Heroes that have a weak laning stage: Spectre, Nyx Assassin, Clockwerk, Spirit Breaker, Omniknight, Pudge.

* 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.

* Heroes with low mobility that rely on spells: Zeus, Lina, Crystal Maiden.

* 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.

* Night Stalker's Crippling Fear at night prevents Shadow Walk for an extended period of time and his Void will make Phase Boots useless. If Night Stalker has True Sight, he can shutdown Bounty Hunter's sneak kill.

* 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.

* 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.

* 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.

* Crippling Fear makes Night Stalker one of the best early game gankers to shut down Anti-Mage.
* Night Stalker's low mana pool causes him to take little damage from Mana Void.

* 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.

* Void can interrupt Icarus Dive.
* His Crippling Fear's silence will shutdown a spell caster Phoenix.
* However, Phoenix punishes Night Stalker with Supernova because it will turn night into day, and it has a higher priority than Dark Ascension, effectively canceling the passive bonuses Night Stalker gets from Hunter in the Night.

* 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 with low mobility that rely on spells: Zeus, Lina, Crystal Maiden.

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

* Heroes that have a weak laning stage: Spectre, Nyx Assassin, Clockwerk, Spirit Breaker, Omniknight, Pudge.

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

* Heroes that have a weak laning stage: Spectre, Nyx Assassin, Clockwerk, Spirit Breaker, Omniknight, Pudge.

* The long silence of Crippling Fear at night prevents Mirana from escaping with Moonlight Shadow and Leap. She also has really low base health, so Night Stalker can usually kill her during one cast of Crippling Fear at night.
* With Dark Ascension and Gem of True Sight, Night Stalker can find and kill Mirana, and he is a tanky hero capable of fighting Mirana any stage of the game.

* Crippling Fear can silence Faceless Void for a long time, preventing him from using his Time Walk and Chronosphere.

* 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.

* 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.

* 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.

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

* 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.

* 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.

* Night Stalker has a huge, almost instant silence through Crippling Fear. The main problem is that he can get it off while Queen of Pain barely has any vision of him if he creeps up to her during Dark Ascension. She'll have to play very carefully before she gets a Black King Bar or a Eul's Scepter of Divinity.

* 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.

* 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.

* Crippling Fear is a good way to shut down and gank Invoker in the early game..
* Void deals good damage to Invoker and makes escaping harder.
* With Hunter in the Night and Void, Invoker can't get away from Night Stalker and won't be able to catch him with Sun Strike during the night.

* 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.

* 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.

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

* Heroes with weaker mobility will struggle to keep up with Night Stalker: Gyrocopter, Ursa, Drow Ranger

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

* 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.

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

* 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.

* 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.

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

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

* 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 weaker mobility will struggle to keep up with Night Stalker: Gyrocopter, Ursa, Drow Ranger

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

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

* Heroes that have a weak laning stage: Spectre, Nyx Assassin, Clockwerk, Spirit Breaker, Omniknight, Pudge.

Additional:
* Void's mini-stun and silence from Crippling Fear will stop Pudge from using Dismember or turning off his Rot.
* Night Stalker has naturally high health, strength gain and common itemization for survivability through magic resistance, making Night Stalker a poor target for Pudge.

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

* Heroes with weaker mobility will struggle to keep up with Night Stalker: Gyrocopter, Ursa, Drow Ranger

* 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.

* Any heroes with silences can negate the majority of Outworld Destroyer's damage output: Death Prophet, Night Stalker, Drow Ranger, Doom .

* Heroes that have a weak laning stage: Spectre, Nyx Assassin, Clockwerk, Spirit Breaker, Omniknight, Pudge.

* Heroes with long disables, like Lion, Night Stalker, or Legion Commander, can prevent Oracle from using spells or items.

* Heroes with low health: Lich, Crystal Maiden, Lion.

* 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.

* 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.

* 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.

* 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.

* 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.

* Crippling Fear silences nearby heroes and cannot be dispelled, which hinders Rubick's way to retaliate when being jumped on.
* With Hunter in the Night and Dark Ascension, Night Stalker can find Rubick easily in teamfights. The two spells grants more than enough damage to hunt Rubick down without defensive items.

* Heroes with low health: Lich, Crystal Maiden, Lion.

* The long silence of Crippling Fear at night prevents Weaver from using his Shukuchi or Time Lapse.
* With Dark Ascension and Gem of True Sight, Night Stalker can easily find and probably kill Weaver.
* Hunter In the Night's attack speed bonus removes The Swarm's beetles very quickly.

* Storm Spirit is absolutely helpless if caught within Night Stalker's silence range.
* Common items a Storm Spirit will build will not remove the AoE silence.
Additional:
* Crippling Fear is a silence that can last up to 8 seconds during night, rendering Storm Spirit tied limited to his items in a fight.
* Dark Ascension allows Night Stalker to initiate on Storm Spirit across the impassable terrain around the middle lane, rendering Storm vulnerable in the early game and prevent him from snowballing.

* Crippling Fear prevents Keeper of the Light from using his spells to keep his team alive during team-fights.
* Dark Ascension is very strong against Keeper of the Light, as it allows Night Stalker to jump the backline and quickly kill the squishy Ezalor, especially when combined with the slow from Void.
Additional:
* Keeper of the Light's Aghanim's Scepter upgrade loses much of its power, due to Night Stalker being able to reduce the duration of daytime by a lot.

* Night Stalker is one of the best heroes to find (and silence) Tinker in the trees during Dark Ascension.
Additional:
* Night Stalker can easily find Tinker in the trees during Dark Ascension.
* Void's mini-stun will stop Rearm and Keen Conveyance
* Crippling Fear's silence will prevent Tinker from fighting back, as Tinker relies on his spells.

* The long silence at night prevents Clinkz from escaping with invisibility if Night Stalker can sneak up on him. He also has really low base health, so Night Stalker can usually kill him alone during one cast of Crippling Fear at night.