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

* Press the Attack dispels Flaming Lasso.
* Batrider is unlikely to win a Duel in any stage of the game.

* Sniper's low mobility and lack of defensive abilities makes him an easy gank target for the entire game, especially if Blink Dagger is picked up.

* 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.

* Press the Attack can dispel Laser's blind while providing great attack speed and health regeneration.
* Once caught in a Duel, Tinker, who completely relies on his spells to be effective, has little chances of survival with his low health pool and armor.

* 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.

* Legion Commander can use Press the Attack on an ally to dispel the disable of Dismember. The bonus health regeneration also partially counters the damage of Rot
* Duel can be used on Pudge whilst Rot is active, disabling toggling which may result in a lethal health drain that leaves Legion Commander with a successful duel.

* 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.

* 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.

* Duels prevents Queen of Pain from using Blink, which may force her to purchase a Linken's Sphere or go for the spell block talent.
* Because Queen of Pain is also not a right-click hero, Legion won't have much difficulties in duels.
* Press the Attack dispels Shadow Strike's debuff.

* Duel's long duration prevents Weaver from activating Time Lapse or escaping with Shukuchi.

* 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.

* Duel is a great initiation to target Crystal Maiden with, as it prevents her from using Freezing Field or any other abilities and allowing the enemy team to quickly kill her before she can aid her team in a fight.

* 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 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.

* Drow Ranger's low mobility and lack of defensive abilities makes her an easy gank target in the early to mid-game.
* A Dueling Drow Ranger will lose her precious Marksmanship, reduce her damage output significantly and will more likely lose that Duel.

* 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.

* Chen's fragilty and low mobility make him an enticing Duel target.
* Overwhelming Odds and Moment of Courage can take advantage of converted creeps' numbers.
* With enough damage from Duel stacks, Legion Commander can also often kill any of Chen's unfortunate allies before he can use Hand of God.
Additional:
* Chen's frailty and low mobility make him an enticing Duel target.
* Overwhelming Odds and Moment of Courage can take advantage of converted creeps' numbers.
* With enough damage from Duel stacks, Legion Commander can also often kill any of Chen's unfortunate allies before he can use Hand of God.

* Heroes that can disable or silence Silencer for a long time, such as Bane and Legion Commander, can lock down Silencer while their allies put him down.

* 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.

* 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.

* Heroes who rely on summons will see them destroyed easily by Overwhelming Odds: Lycan, Arc Warden, Warlock, Chen

* 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.

* Press the Attack can dispel the blind from Blinding Light from a hero.
* Duel can be used to instantly take Keeper of the Light out of a team-fight.

* Nyx Assassin can reflect Life Break with Spiked Carapace.

* Carries that can out damage Huskar will do well against him: Legion Commander, Faceless Void, Troll Warlord, Phantom Assassin.

Additional:
* Life Break is almost suicidal when used on Legion Commander, as it invites an instant Duel and Legion Commander herself is a natural Blade Mail carrier.
* Huskar's low survivability and mostly on low health makes him particularly vulnerable to Legion Commander's high physical damage.

* 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

* Heroes rely on their debuff to control the opponent will have a hard time against Press the Attack: Venomancer, Earth Spirit, Ogre Magi

Additional:
* Press the Attack dispels Venomous Gale and Poison Sting from Legion Commander or her teammates.

* Duel makes Bristleback fight Legion Commander face to face, forcing him to take full damage.
* Press the Attack dispels the slow from stacks of Viscous Nasal Goo.
Additional:
* When dueled, Bristleback will have to face Legion head on, not allowing his passive Bristleback to come into effect.

* 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.

* 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.

* 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.

* Duel's long duration prevents Terrorblade from swapping his health with Sunder.
* Overwhelming Odds deals high damage to Terrorblade's illusions.

* Overwhelming Odds deals high damage to Phantom Lancer's illusions.
* Duel's long duration prevents Phantom Lancer from using Doppelganger.

* Legion Commander's spells are relatively useless to Rubick, as Duel isn't suitable for someone as squishy as Rubick.
* Press the Attack can be useful, but its high mana cost will leave you with little mana.
* Overwhelming Odds only does damage and gives a movement speed bonus, Rubick can't do much with the extra move speed.
* Generally, you will be a prime target for Legion Commander's Duels, as Rubick is relatively frail.

* 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.

* 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.

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

* Duel is a great initiation to kill Death Prophet before she can cast Exorcism. Furthermore, Legion Commander often builds Blade Mail and can reflect Exorcism's damage to kill Death Prophet easily.

* 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.

* 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.

* 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'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.

* 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.

* Overwhelming Odds is great at killing many stacked up spiderlings, thus giving Legion Commander a large buff.
* Duel is a reliable way to lock down Broodmother, preventing her from running into the treeline.
Additional:
* Overwhelming Odds's damage stacks with each enemy unit in its radius. If this hits Broodmother and a large number of spiders it can deal significant amounts of damage.
* Moment of Courage has a high chance to proc if Broodmother and all of her spiders are attacking her.
* Duel can keep Broodmother in place long enough for Legion's team to kill her.

* Searing Arrows and Clinkz physical damage items is almost suicidal when used on Legion Commander, as it invites an instant Duel and Legion Commander herself is a natural Blade Mail carrier.
* Duel locks down Clinkz for a long duration, preventing him from escaping with Skeleton Walk.

* Heroes with invisibility: (Riki, Clinkz, Nyx Assassin

* Legion Commander's Overwhelming Odds works similar to Echo Slam but with less damage.

* 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.

* 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 rely on their debuff to control the opponent will have a hard time against Press the Attack: Venomancer, Earth Spirit, Ogre Magi

* 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.

* Heroes with long lockdowns: Shadow Shaman, Legion Commander.

* Heroes who rely on illusions will see them destroyed easily by Overwhelming Odds: Phantom Lancer, Chaos Knight, Terrorblade, Naga Siren

* Pudge, Legion Commander and Axe will make the match a living hell for you, since they are known for surprise attacks from the fog and quickly killing low HP heroes. They can also interrupt your channeling, Legion being especially problematic, as she can use Press the Attack on an ally who is hexed as well.

* 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 with low health will die easily during Duels, and can be farmed for damage in the early game: Crystal Maiden, Lich, Techies, Rubick

* Special mention to Legion Commander, as she can lock down Void Spirit for a long amount of time without worrying too much about being killed by him during the Duel.

* 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

* Heroes rely on their debuff to control the opponent will have a hard time against Press the Attack: Venomancer, Earth Spirit, Ogre Magi

* Enigma is fragile, and lacks escapes, being dependent on Blink Dagger for mobility. Ganking Heroes or Heroes with burst damage will likely kill him before he can do anything. Such Heroes include: Lina, Lion, Puck, Slark, Nyx Assassin, etc.

Additional:
* Enigma's uncontrollable damage from Malefice and Midnight Pulse make him easy to stun with Spiked Carapace.
* Black Hole can be easily interrupted by Impale or Spiked Carapace.

* 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

* 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.

* 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.

* 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.

* Duel renders Anti-Mage's escape capabilities with Blink and Counterspell useless.
* A good initiation from Legion Commander and her team is enough to effortlessly kill Anti-Mage.
Additional:
* Counterspell offer no protection against Duel at all.
* Duel locks down Anti-Mage for a long duration, preventing him from escaping with Blink. One successful Duel initiation is usually enough for Legion Commander's team to kill Anti-Mage.

* Another great threat to Riki since her Duel forces him to fight from the front and expose him for the entire duration, almost always guaranteeing an easy win (unless Riki has allies helping him).

* Legion Commander is both good and bad vs Mars, on the plus side she can dispel Spear of Mars with Press the Attack and is a good Silver Edge carrier. Mars is also not the ideal duel target, since he's not very useful after using his abilities anyway.

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

* Duel is very effective against Io due to its low health and armor.

* Heroes who can dispel will be able to remove Shadow Poison before Shadow Demon can build up a big stack, or remove Soul Catcher's debuff to instantly bring the health of affected heroes back to a considerable amount: Abaddon, Slark, Legion Commander, Oracle.

* 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.

* Heroes with low health will die easily during Duels, and can be farmed for damage in the early game: Crystal Maiden, Lich, Techies, Rubick

* 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.

* 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.

* 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.

* 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.

* 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.

* Duel pierces spell immunity and forces him to attack Legion Commander, making him unable to use Omnislash.

* Heroes that can protect or dispel stunned allies such as Legion Commander, Outworld Devourer, Shadow Demon and Oracle can reduce the effectiveness of Sacred Arrow.

* Heroes who rely on summons will see them destroyed easily by Overwhelming Odds: Lycan, Arc Warden, Warlock, Chen

* 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.