* Vendetta breaks Untouchable and deals great damage against her.
* Enchantress' lack of mobility makes her a primary target for ganking with Vendetta.
* Spiked Carapace can reflect Impetus and stun Enchantress.
* Mana Burn can deal tremendous damage against her due to being an Intelligence hero.
Additional:
* Vendetta disables Untouchable.
* Spiked Carapace reflects the damage from Impetus.
* Enchantress is a rather squishy hero, making her fall easily to Nyx Assassin's high burst damage.

* Untouchable won't mitigate Venomancer's magical damage, and Enchantress is vulnerable to magic damage.
* Both Venomous Gale and Poison Nova lowers the amount of healing received by Enchantress and her allies from Nature's Attendants.

* Plague Wards are very hard for Batrider to play against as they provide a lot of vision as well as disable Blink Dagger for a long duration.

* Nyx can walk into Firefly with Spiked Carapace and stun Batrider if he has no Spell Immunity.

* Unless Puck is facing the direction he wants to blink while in Phase Shift, the Venomous Gale and Poison Nova combo consistently ticks many times over several seconds, making it very difficult to use Blink Dagger towards the other direction. Puck's slow turning rate makes this even worse.

* Nyx Assassin can take advantage of every one of Puck's weaknesses. His entire skill set is very effective in countering Puck.
* Because Illusory Orb is such a slow moving projectile, Nyx Assassin can simply walk into the orb and activate Spiked Carapace, stunning Puck and setting up an easy Impale. This can be circumvented by using Phase Shift while the orb is traveling, however, that means that Puck cannot use Phase Shift to dodge any other skill nor use it to safely blink away from a fight.
* Puck is an intelligence hero that likes to build intelligence items such as Eul's Scepter of Divinity, Scythe of Vyse, and Dagon. This makes Mana Burn that much more deadly against Puck.
* An ill-timed Phase Shift can easily set himself up to be stunned by Impale.
* Puck's low base armor and below average agility gain means he is always susceptible to Vendetta.
Additional:
* Illusory Orb is easy to reflect with Spiked Carapace, either stunning Puck and setting up an easy Impale or forcing a premature Phase Shift.
* Puck is an intelligence hero that tends to build intelligence items, making it vulnerable to Mana Burn.
* An ill-timed Phase Shift can easily set Puck up to be stunned by Impale.
* Puck's low base armor and below average agility gain mean it is always susceptible to Vendetta.

* Heroes with break abilities: Nyx Assassin, Shadow Demon (with Aghanim's Scepter), Viper.

* Venomancer's spells all deal magical damage, ignoring Bulwark.
* Venomancer's multiple slows are especially effective at kiting Mars.
* Plague Wards can attack through Arena Of Blood.
Additional:
* Venomancer's poison attacks are all magical damage, ignoring Bulwark.
* Venomancer's multiple slows are especially effective against Mars' low mobility.
* Plague Wards can attack through Arena of Blood.

* 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.

Additional:
* Due to lack of magic resistance, Venomancer poisons eats through Windranger's health.

* Many of Nyx Assassin's abilities are good against Windranger.
* Impale is great for stunning Windranger and allowing additional disables to be landed.
* Mana Burn is useful against Windranger's decent intelligence growth and also burns some mana, preventing her from using more abilities.
* Spiked Carapace is easy to use against Powershot.
* Vendetta allows Nyx Assassin to sneak up on and deal massive damage to Windranger without giving Windranger a chance to use Windrun to evade it.
* Nyx Assassin's item build allows him to easily deal with Windranger.

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

* Heroes who can drain mana can make Omniknight useless after he uses one or two abilities: Lion, Anti-Mage, Nyx Assassin

* Mana Burn is strong against Keeper of the Light due to his high mana pool.
* Spiked Carapace can be used to reflect Illuminate damage and stun Keeper of the Light.
* Vendetta allows Nyx Assassin to follow Keeper of the Light around if he tries to split-push.

* With Vendetta, Nyx Assassin can move closely to Ember Spirit when he's farming with his Flame Guard and use Spiked Carapace with Impale to provide a reliable and long disable.
* Mana Burn is also good, as Ember Spirit relies on his limited mana pool for the early to midgame.
Additional:
* Spiked Carapace can be easily triggered by Flame Guard or Battle Fury, setting up a deadly Impale.

* Venomancer's magical damage-over-time poisons will constantly put Tree Dance on cooldown, greatly diminishing Monkey King's mobility.
* Venomous Gale and Poison Nova will hit Monkey King when he is perched on a tree, or disguised with Mischief.
* However, Venomancer is also easily ganked by Monkey King if caught by surprise.
Additional:
* Venomancer's magical damage-over-time poisons putting Tree Dance on cooldown, greatly diminishing Monkey King's mobility.
* Venomous Gale and Posion Nova will hit Monkey King when he is perched on a tree, or disguised by Mischief.

* Outworld Devourer's high intelligence gain and fragility makes him an easy target for a massive Mana Burn, as well as killing him outwards with Nyx Assassin's high burst damage.
* Astral Imprisonment can be easily exploited by Nyx Assassin with his abilities. As long as Astral Imprisonment was not cast on Nyx Assassin, it will make an opportunity for an easy stun, either by Spiked Carapace (if Outworld Devourer hid his allies or your allies) or Impale (if he hid himself). If Astral Imprisonment was cast on Nyx Assassin, using Spiked Carapace while banished will proc the stun after the disable, since Spike Carapace has a 0 second cast time and Astral Imprisonment deals damage right after the disable ends.
* An ill-timed Sanity's Eclipse or well timed Spiked Carapace can deal a lot of damage to Outworld Devourer and stun him, unless Outworld Devourer used Black King Bar beforehand.
Additional:
* Outworld Devourer's high mana pool, high intelligence, and low health makes him a prime target for Mana Burn.
* If timed correctly, Spiked Carapace will return the full damage from Sanity's Eclipse back to Outworld Devourer. Even a reflected Arcane Orb can deal significant damage and make him vulnerable to a follow-up from Nyx Assassin.
* Spiked Carapace is also the perfect tool against Astral Imprisonment: if used on Nyx, he can reflect the damage back as he comes out of the prison by casting the ability while imprisoned; if used on any other target, Nyx can come and stand close to it and use it to reflect the damage.

* His whole skillset acts like a counter to Tinker:
* Impale prevents Tinker from blinding Nyx Assassin or fighting back, while giving Nyx' allies time to catch up to Tinker's position.
* Mana Burn generally deals more damage to intelligence based heroes like Tinker
* Spiked Carapace can stun Tinker at a moment of Nyx Assassin's choosing if March of the Machines has been cast. It is also quite easy to time Spiked Carapace against Heat Seeking Missiles.
* Vendetta allows Nyx to approach Tinker in the trees or wait for him in common hiding spots and deal heavy damage to his low armor.
Additional:
* March of the Machines and Heat-Seeking Missile allow easy Spiked Carapace stuns.
* As a fragile hero that relies on mana and intelligence items, Tinker is vulnerable to Mana Burn.
* Nyx Assassin's stuns can interrupt Rearm and leave Tinker helpless.

* Aggressively Poofing and Earthbinding is not going to end well against Venomancer, as he will be an easy target for Poison Nova.
* Venomancer constant slows greatly reduce Meepo's mobility.

* With her passive Split Shot, Medusa can be easily interrupted by Spiked Carapace during combat, especially during her precious Stone Gaze.
* Mana Burn quickly destroys Mana Shield, especially if Medusa only increases her mana pool by bolstering intelligence (which has the added bonus of increasing Mana Burn's damage).
* Uncontrollable damage from Mystic Snake and Split Shot can trigger Spiked Carapace.
* Medusa lacks single target damage, making a Burrowed Nyx Assassin hard to kill.
Additional:
* Level 4 Mana Burn burns 38,5% of Medusa's mana every 4 seconds if Medusa only increases her mana pool with intelligence. Additionally, 60% of the Mana Burn damage gets mitigated by Mana Shield, burning even more mana.
* Due to the passive nature of Mystic Snake and Split Shot, it can possibly proc Nyx's Spiked Carapace if he's within range of Medusa's abilities and isn't invisible.
* Medusa lacks single target damage, making Nyx with Aghanim's Scepter extremely hard to deal with if Medusa is the team's main damage source.

* Mana Burn completely drains Pudge's little mana which may render Meat Hook & Dismember unusable.
* Impale and Spiked Carapace used to cancel Dismember if timed perfectly.
* Vendetta grants Nyx Assassin invisibility and a high degree of mobility for a long time, which can make Nyx a difficult target to hook. In addition, it also scouts out Pudge's location and surprising him with his attack, Impale and Mana Burn.

* Venomancer's damage over time can force Chen to use Hand of God prematurely, potentially wasting a chance to save his allies during a teamfight.

* Heroes with damage burst can often kill Chen or his allies before he can use Hand of God: Lina, Techies, Shadow Fiend, Pugna, Nyx Assassin.

* A good Nyx can reflect Queen of Pain's Sonic Wave with his Spiked Carapace, or even initiate a gank on her in Vendetta while she farms a creep wave with Scream of Pain.
* Her strength to intelligence ratio is bad enough that he should be able to kill her without even requiring a Dagon, provided he can get his full combo off.

* Silencer is rather squishy and has poor mobility without items, making him an easy target for Nyx.
* Mana Burn will deal increasing damage for each 2 points of intelligence Silencer has stolen, turning Silencer's intelligence steal against him.

* Nyx Assassin's Spiked Carapace will stun Leshrac when hit by any of his AOE abilities.
* Mana Burn deals high damage due to Leshrac's high intelligence gain and burns a large amount of Leshrac's essential mana pool.

* Venomancer can simultaneously scout Magnus hiding in trees and putting Blink Dagger on cooldown with Plague Wards, which makes Magnus real problems to blink and initiate.
Additional:
* Similar to Night Stalker, Venomancer can simultaneously scout Magnus hiding in trees and put Blink Dagger on cooldown with Plague Ward, which gives Magnus problems when trying to blink in and initiate.

* Windranger's Focus Fire tears apart Templar Assassin's refraction very quickly and easily bursts here down due to her low health pool against Windranger's immense attack speed
* Templar Assassin's "Psionic Trap" doesn't slow down Windranger due to her skill Windrun
* Templar Assassin's high damage can also be easily evaded thanks to Windrun's 100% evasion
Additional:
* Venomous Gale and Plague Wards allow to quickly melt through Refraction charges.
* Both Poison Nova and Venomous Gale hit invisible units, so Meld cannot be used defensively.

* Venomancer's slows and magical damage-over-time work well against Axe's complete lack of mobility.
* Plague Ward is especially useful for slowing down Axe, and revealing him before he initiates, as well as putting his Blink Dagger on cooldown.
Additional:
* Venomancer's slows and magical damage-over-time work well against Axe's complete lack of mobility.
* Plague Wards is especially useful for slowing down Axe, and revealing him before he initiates, as well as putting his Blink Dagger on cooldown.
* For the same reasons, Venomancer is a good ally for Axe when the situation is reversed.

* Spiked Carapace stops Snapfire's Mortimer Kisses.
* Snapfire's low armor and agility gain means that Vendetta will deal a decent amount of damage.

* Venomancer's slows and magical damage-over-time works well against Earthshaker's which completes lack of mobility.
* Plague Wards is useful for slowing and kitting down Earthshaker, revealing him from initiating and re-initiating and putting his Blink Dagger on cooldown if Venomancer has vision over Earthshaker.
Additional:
* Earthshaker can be kited by Venomancer's slows, which is lack of mobility.
* Plague Wards is very useful for slowing and kitting down Earthshaker, revealing him from initiating and re-initiating and putting his Blink Dagger on cooldown.

* Spiked Carapace allows Nyx to get an easy long-duration stun on Weaver once he uses Shukuchi, and then he can follow up with Impale.
* Vendetta works as a great setup for both Impale and Spiked Carapace and can deal decent damage to Weaver. Additionally he can neutralize The Swarm beetles due to his invisibility duration.

* Mana Burn can instantly deplete Tidehunter's low mana pool, especially in the early game, potentially preventing Tidehunter from casting Ravage.
* Ravage's travel time allows Nyx Assassin to easily stun Tidehunter with Spiked Carapace.
* Vendetta offers a very rare break effect, which fully disables Kraken Shell and makes Tidehunter susceptible to follow-up disables.

* Skywrath Mage's low health makes him rather easy prey for Nyx Assassin and his lack of armor generally means he'll take the full brunt of a Vendetta strike.
* Mana Burn is annoying at all stages of the game as it turns Skywrath Mage's high intelligence growth against him.
* Spiked Carapace gives Nyx some degree of protection against Skywrath's spells.

* Venomancer forces Sven to choose between using his Black King Bar or getting constantly slowed by his poison.

* Crystal Maiden has a very bad movement speed, so Impale is easy to land against her. Furthermore, even while trapped by Frostbite, Nyx Assassin can still cast Impale.
* Crystal Maiden has very low armor, so Vendetta is very effective.
* Nyx Assassin has two ways to stop Freezing Field, provided she doesn't get a Black King Bar. He can pop Spiked Carapace and simply walk into the field, or he can use Impale to interrupt the field, since Crystal Maiden has to channel it.
Additional:
* Spike Carapace easily interrupts Freezing Field.
* Frostbite's damage over time sets up an easy Spiked Carapace stun.
* Crystal Maiden is extremely fragile and dies quickly to Nyx Assassin's burst damage.

* Nyx Assassin's high burst damage can be the bane of Dark Willow, as her low health makes it difficult to survive long enough to escape through Shadow Realm.
* Spiked Carapace can be triggered by walking deliberately into Bramble Maze, leaving Dark Willow stunned and defenseless.

* Impale interrupts Upheaval.
* Nyx Assassin Vendetta allows him to escape from Warlock's Upheaval with maximum move speed.
* Warlock's low health pool and mobility can easily take down by Nyx Assassin's burst damage.

* The huge physical damage taken from Vendetta will force Necrophos to use Ghost Shroud, which is good for a followup with Dagon and Ethereal Blade, both of which are common items on Nyx Assassin.
* Using Ghost Shroud also sets Necrophos up for a Mana Burn or Impale.

* Venomancer's poison damage-over-time are very effective against Spectre, which is lack of magic resistance from early to mid game.
* Venomancer's multiple slows greatly reduces Spectre's low mobility, even through Spectral Dagger.
* Plague Wards reveals Spectre while she is hiding on trees.
Additional:
* Venomancer's poison damage over time is very effective against Spectre, who tends to lack magic resistance during the early to mid game.
* Venomancer's multiple slows greatly reduces Spectre's movement speed and mobility.
* Plague Wards can scout out Spectre while she is hiding in trees.

* Vendetta disables Vengeance Aura and allows him to attack Vengeful Spirit with Impale and Mana Burn.
* Spiked Carapace is easy to use against a Wave of Terror or Magic Missile.

* Heroes with high burst damage: Lina, Lion, Luna, Nyx Assassin, Queen of Pain.

* Heroes that can pick you off: Clinkz, Nyx Assassin, Puck, Riki.

* 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.

* Large area-of-effect with delay or require channeling: Enigma, Crystal Maiden, Invoker, Shadow Fiend, Pugna, Keeper of the Light
* The nature of some abilities turn them into an easy target for a turnover from Spiked Carapace:
* Slow-moving projectiles: Skywrath Mage, Tinker, Necrophos
* Large area-of-effect with delay or require channeling: Enigma, Crystal Maiden, Invoker, Shadow Fiend, Pugna, Keeper of the Light
* Deals damage over time: Venomancer, Huskar, Ember Spirit, Dark Seer, Sand King, Doom

Additional:
* Nyx Assassin takes advantage of Invoker's massive intelligence gain and mana pool to do tons of damage using Mana Burn, as the spell does more damage based on the target's intelligence.
* Nyx Assassin can simply activate Spiked Carapace while under many Invoker's abilities to stun him.

* Silence (and mana burns) will be a persistent problem for Phoenix, as it is heavily reliant on its abilities whether defensively or offensively, so heroes like Death Prophet, Skywrath Mage, and even Nyx Assassin must be closely observed to prevent being shut down by these heroes.
* Hexes are a greater threat to Phoenix as they also disable items, preventing Phoenix from dispelling the debuff on its own.

Additional:
* Spiked Carapace reacts on any of the damage over time from Phoenix's abilities and can interrupt Sun Ray and Icarus Dive.

* Nyx Assassin, Bounty Hunter and Slark can all sneak up and kill you, Nyx being particularly deadly. Watch Slark carefully, as he can break either (but not both unless you are making a mistake) of your disables, with Dark Pact and leap out of a serpent ward ring. These heroes, however, rely heavily on escape and are themselves not very durable and none of them can survive a full lockdown with Mass Serpent Ward. Having Sentry Wards can turn you from prey to predator.

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

* Deals damage over time: Venomancer, Huskar, Ember Spirit, Dark Seer, Sand King, Doom
* The nature of some abilities turn them into an easy target for a turnover from Spiked Carapace:
* Slow-moving projectiles: Skywrath Mage, Tinker, Necrophos
* Large area-of-effect with delay or require channeling: Enigma, Crystal Maiden, Invoker, Shadow Fiend, Pugna, Keeper of the Light
* Deals damage over time: Venomancer, Huskar, Ember Spirit, Dark Seer, Sand King, Doom

* Assassinate is easy to reflect with Spiked Carapace for massive damage.
* Shrapnel's area damage can set up an easy stun with Spiked Carapace, especially when combined with Vendetta.
* In the early game, Sniper's low health pool and high intelligence makes him easy prey for Nyx Assassin.

* Vendetta allows Nyx to sneak up on Lion and deal massive damage to him, especially when followed up with an Impale, Mana Burn, or even Dagon.
* Spiked Carapace has the potential to not only nullify Lion's damage, but also cripple and potentially deal massive damage to Lion, especially if he reflects Finger of Death.

* Plague Wards may reveal a hiding Techies. If there's a sentry nearby, they may also reveal a stack of mines hidden in a juking spot.

* Due to Pugna's incredible intelligence growth and terrible strength growth, Nyx should always be able to take you out with his combo, with or without an added Dagon. Mana Burn will deal a large amount of damage in particular, especially in the late game.
* Spiked Carapace is also a great tool versus Pugna. A good player will wait for you in Vendetta until you farm a creep wave with Nether Blast and reflect it back at you as their initiation and setup for Impale.
Additional:
* Nether Blast's animation makes it easy to time Spiked Carapace for a stun.
* Pugna has the largest intelligence gain in the game, making him a prime target for Mana Burn.
* Pugna needs to channel Life Drain, making him easy to hit with Impale.

* Mana Burn is capable of removing most of Storm Spirit's large mana pool, along with dealing heavy damage and quickly depleting his chances of escaping a gank or fight.
Additional:
* Mana Burn removes much-needed mana for Ball Lightning.
* Spiked Carapace triggers on Static Remnant for an easy stun.

* Nyx Assassin has a lot of burst damage from his Impale, Mana Burn, Dagon, and the bonus damage from Vendetta. All of this damage is enough to kill Drow Ranger.
* Nyx Assassin is usually invisible most of the time thanks to his ability Vendetta, which allows him to gank Drow Ranger easily.

* Mana Burn does tons of damage against Lina because of her high intelligence. The mana burn also prevents Lina from casting her full combo.
* Spiked Carapace can easily be used to counter Lina's abilities because of their long cast animation, and could probably kill Lina outright if Laguna Blade is reflected.

* Ethereal state disarms the target and makes them more vulnerable to magic damage, both of which Phantom Assassin despises. Especially Pugna and any hero that is wielding Ethereal Blade, such as Mirana, Nyx Assassin or Morphling.

* Once you've taken a point in Retaliate, Nyx can easily initiate on you: he can use Spiked Carapace and hit you with Vendetta. The damage from Retaliate will be reflected back to you, stunning you with no chance to react after he's revealed himself, and should guarantee a successful Impale.

* Venomancer's magical damage-over-time poisons greatly reduce Bounty Hunter's mobility.
* Venomous Gale, Plague Wards and Poison Nova with True Sight items can allow Venomancer and his teammates to gank Bounty Hunter while he is roaming alone.

* Nyx Assassin can reflect Life Break with Spiked Carapace.

* Venomous Gale, Poison Sting and Poison Nova deal damage over time and will chip away at Gravekeeper's Cloak in addition to slowing an already sluggish hero.
* Venomancer's normal attacks deal Poison Sting and will chip away at Gravekeeper's Cloak.