Nyx Assassin
* 
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.
Phoenix
* 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.
Nyx Assassin
* 
Rage allows Lifestealer to freely attack Nyx Assassin and hunt him down if Vendetta is on cooldown. Nyx Assassin cannot counter Rage with Spiked Carapace because Rage gives Lifestealer spell immunity. And besides Vendetta, Nyx Assassin has no other way of dealing damage to Lifestealer while he is spell immune.
* 
Open Wounds from 
Aghanim's Shard allows Lifestealer to severely slow down Nyx Assassin while also allowing his team to recover themselves while attacking Nyx Assassin. Open Wounds can also fester and spread if Nyx Assassin takes enough damage that will trigger the spread while he is affected with Open Wounds.
* 
Infest combined with an ancient creep makes Nyx Assassin an easy target to surprise with 
Dust of Appearance or a 
Gem of True Sight. 
Aghanim's Scepter upgraded Infest can also allow Lifestealer to infest, disarm and freely attack Nyx Assassin from within. and Nyx Assassin cannot counter this with Spiked Carapace because Lifestealer is invulnerable while attacking the infested enemy hero from within.
* Overall, any attempt for Nyx Assassin to gank and kill Lifestealer will hurt Nyx Assassin more than Lifestealer.
Additional:
* Like with Juggernaut's 
Blade Fury, Rage allows Lifestealer to freely attack Nyx Assassin and hunt him down if 
Vendetta is on cooldown. Nyx Assassin cannot counter Rage with Spiked Carapace because Rage gives Lifestealer spell immunity. And besides Vendetta, Nyx Assassin has no other way of dealing damage to Lifestealer while he is spell immune.
* Open Wounds from Aghanim's Shard allows Lifestealer to severely slow down Nyx Assassin while also allowing his team to recover themselves while attacking Nyx Assassin. Open Wounds can also fester and spread if Nyx Assassin takes enough damage that will trigger the spread while he is affected with Open Wounds.
* Infest combined with an ancient creep makes Nyx Assassin an easy target to surprise with Dust of Appearance or a Gem of True Sight. And similarly to Juggernaut's 
Omnislash and 
Swiftslash from Aghanim's Scepter, Aghanim's Scepter upgraded Infest can also allow Lifestealer to infest, disarm and freely attack Nyx Assassin from within. And Nyx Assassin cannot counter this with Spiked Carapace because Lifestealer is invulnerable while attacking the infested enemy hero from within.
* Like with Juggernaut, any attempt for Nyx Assassin to gank and kill Lifestealer will hurt Nyx Assassin more than Lifestealer.
Phoenix
* Heroes with spell immunity-granting spells will render Phoenix useless against them, as Phoenix has almost no spell immunity-piercing ability, other than the stun at the end of 
Supernova: 
Lifestealer, 
Juggernaut.
Nyx Assassin
* Heroes with invisibility will be detected by Thirst when they have low enough health: 
Bounty Hunter, 
Templar Assassin, 
Riki, 
Clinkz, 
Weaver, 
Treant Protector, 
Nyx Assassin.
Additional:
* While Burrowing, Nyx is an easy target for a 
Blood Rite, and his only way to counter it is a well-timed Spiked Carapace.
* 
Thirst is always a threat to Nyx Assassin, hindering his attempt of escape using Vendetta and rendering him unable to surprise Bloodseeker's allies.
* 
Rupture also prevents Nyx Assassin from escaping with Vendetta, as it forces him to stay still.
Phoenix
* Phoenix expends health to use its abilities, making it a good target for Thirst.
* Rupture deals heavy damage against 
Icarus Dive.
Additional:
* Although Blood Rite can be easily avoided, if it does hit, its lengthy silence and pure damage can be a severe punishment for a slow, unobservant, or simply unfortunate Phoenix.
* His Rupture can turn Icarus Dive into a suicide option, and it cannot be dispelled, meaning even if Phoenix completes a Supernova, choosing to Dive may just cut its health back down.
* And finally, due to Phoenix's health costs, too much careless ability spamming may just put Phoenix into Bloodseeker's vision through Thirst, making it a very tempting ganking target.
Nyx Assassin
* Heroes who build mana boosting items but have low mana regeneration are especially vulnerable against Mana Break and Mana Void: 
Timbersaw, 
Slark, 
Shadow Fiend, Clinkz, 
Bristleback Nyx Assassin, 
Magnus
Phoenix
* Anti-Mage dispels Phoenix's slows with 
Manta Style.
* Anti-Mage can Blink directly next to Supernova, giving him more time to destroy the egg.
Nyx Assassin
* Heroes who build 
Black King Bar as either core or situational item will be able to fight back against Nyx Assassin and freely attack him as Spiked Carapace cannot pierce spell immunity at all: 
Axe, 
Broodmother, 
Dawnbreaker, 
Enigma, 
Huskar, 
Jakiro, 
Legion Commander, 
Lina, 
Luna, 
Lycan, 
Slardar, Slark, 
Troll Warlord, 
Witch Doctor.
Phoenix
* Any hero with high attack speed will be a threat to Phoenix when it initiates, as they can easily tear down a Supernova, perhaps even while debuffed by Fire Spirits: Juggernaut, Clinkz, Troll Warlord, 
Beastmaster, Lina.
Additional:
* Due to Fervor and Battle Trance, Troll Warlord is one of the best heroes to deal with Supernova.
Nyx Assassin
* Heroes who build Black King Bar as either core or situational item will be able to fight back against Nyx Assassin and freely attack him as Spiked Carapace cannot pierce spell immunity at all: Axe, Broodmother, Dawnbreaker, Enigma, Huskar, Jakiro, Legion Commander, Lina, Luna, Lycan, Slardar, Slark, Troll Warlord, Witch Doctor.
Phoenix
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: 
Anti-Mage, 
Earth Spirit, 
Faceless Void, Magnus, 
Mirana, 
Monkey King, 
Morphling, 
Pangolier, 
Phantom Assassin, 
Phoenix, 
Puck, 
Queen of Pain, Riki, 
Sand King, 
Spirit Breaker, Timbersaw, 
Tusk.
Nyx Assassin
* Impale and Spiked Carapace stun can be instantly dispelled by Aphotic Shield.
* Abaddon can use Borrowed Time and easily heal for the duration of Borrowed Time by Nyx's burst damage.
Phoenix
* Heroes that deal damage over time will also fail to bring down Abaddon and his allies, such as Huskar, 
Venomancer, or Phoenix.
Nyx Assassin
* Nyx Assassin might not kill Abaddon with his nuke, but a support Abaddon will struggle to protect an ally from him.
Phoenix
* Phoenix does significant magic damage over time which can either be dispelled or negated by Fate's Edict.
* Oracle's burst damage potential can prove lethal to Phoenix, as they already have to sacrifice health to cast their basic skills.
Nyx Assassin
* Heroes that have a weak laning stage: 
Spectre, Nyx Assassin, 
Clockwerk, Spirit Breaker, 
Omniknight, 
Pudge.
Phoenix
* 
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.
Phoenix
* Phoenix turns night to day, overriding Dark Ascension during Supernova.
Nyx Assassin
* Nyx Assassin wants to start ganking as soon as he gets his Vendetta. Keeping him Tracked prevents him from ganking, and thus from doing his job in the game.
* Nyx Assassin has a lot of armor and health regen, making the nuke damage from Shuriken Toss very good against him.
Additional:
* 
Track hinders Nyx Assassin's ganking and escaping attempts with Vendetta, making him an easy kill for gold as well.
* Bounty Hunter can also use Track on Nyx Assassin while he has Spiked Carapace active without getting stunned as Track deals no damage at all before using 
Shuriken Toss.
Nyx Assassin
* 
Cyclone from Storm in 
Primal Split can waste Nyx's Spiked Carapace, since its duration is shorter than the Cyclone's.
Phoenix
* Earthbind can prevent Phoenix from using Icarus Dive, the only escaping mechanism of this hero.
* Heavy burst damage from Poof can easily kill Phoenix even when it slows down all the Meepos with 
Fire Spirits.
* Meepo's clones destroy the Phoenix Sun from Supernova in no time, even when they are slowed down by Fire Spirits.
* Meepo's naturally high magic resistance gives Phoenix a hard time with bursting him down. He can even turn the tide if Icarus Dive is on cooldown.
Additional:
* Meepo is unlike any other multi-unit enemy Phoenix may face in the battlefield. Unlike illusion-based heroes like 
Phantom Lancer or 
Chaos Knight, Meepo's clones are not illusions, meaning they can deal full damage to the Phoenix Sun if all four (or five) are present.
Nyx Assassin
* Lycan's high health allows him to easily shrug off Nyx Assassin's burst damage and fend him off.
* As Lycan commonly buys Black King Bar, he can use it to freely attack Nyx Assassin and chase after him with 
Shapeshift.
* Lycan can also use his wolves from 
Summon Wolves to attack Nyx Assassin while he has Spiked Carapace active without getting stunned himself.
Phoenix
* Tempest Double, Magnetic Field's attack speed bonus, and Arc Warden's high attack range will easily destroy a Phoenix using Supernova much faster than usual.
* Phoenix is very weak against pushers, especially those like Arc Warden who can kill him easily, as his skillset works best in teamfights.
Additional:
* His 
Tempest Double is not an illusion, but rather a full hero unit, which effectively reduces half of the Supernova's health. His 
Magnetic Field can tremendously boost his attack speed, allowing him to destroy Supernova in no time even when he's affected by Fire Spirits.
Phoenix
* Ursa can easily unleash a number of attacks in an incredibly short amount of time, easily destroying the Supernova in a couple of seconds regardless of Fire Spirits' debuff. His 
Enrage also dampens any damage Phoenix might toss at his direction, as well as remove any debuffs Phoenix may place on him.
Nyx Assassin
* Centaur's low Intelligence makes Mind Flare do low damage.
* With some creative skill builds, Centaur's Hoof Stomp stun duration should always last longer than Spiked Carapace stun, so escaping unscathed is hard for Nyx.
* With 
Blink Dagger and detection, Centaur can devastate Nyx in the open.
* However, bear in mind that Nyx can also easily initiate on Centaur Warrunner as well if he uses Spiked Carapace in anticipation, and with Vendetta. The damage from Retaliate will be reflected back to Centaur Warrunner, stunning him with no chance to react after he's revealed himself, and should guarantee a successful Impale.
Phoenix
* Marci can destroy Supernova by herself with Unleash at any stage of the game.
* Phoenix is squishy hero with low armor and is very vulnerable for Rebound and Sidekick at the laning stage.
Nyx Assassin
* Heroes who rely on damage over time as Spiked Carapace can block and reflect only one instance of damage: Jakiro, 
Viper, Venomancer, Huskar, 
Ember Spirit, 
Dark Seer, Sand King, 
Doom, Dawnbreaker. However, this also means they are easily stunned.
Phoenix
* Huskar's high attack speed can counteract Fire Spirits, and easily destroy the Supernova.
Additional:
* 
Berserker's Blood will let Huskar easily face down a Supernova with increased attack speed.
* Icarus Dive may not be an easy escape from Huskar either as he can chase Phoenix during it with 
Life Break if Huskar times it right.
* However, Phoenix can buy items which can
Nyx Assassin
* Nyx Assassin can reflect Life Break with Spiked Carapace.
Phoenix
* Chemical Rage kills Phoenix very quickly in Supernova.
Nyx Assassin
* Even though Nyx Assassin can easily kill Luna with his high burst damage, Luna can also do the same to him if he is not careful.
* 
Lucent Beam can deal a fair amount of damage to Nyx Assassin if he has no Spiked Carapace available to use. Although Luna should be patient using Lucent Beam on Nyx Assassin when he uses Spiked Carapace.
* As Luna commonly buys Black King Bar, she can use it to freely attack Nyx Assassin whenever he tries to defend himself with Spiked Carapace during teamfights. Luna can also buy 
Eye of Skadi and Manta Style to survive Nyx Assassin's burst damage and distract him.
* Though Vendetta can deal serious damage to Luna and avoid 
Eclipse, smart Luna will always buy Dust of Appearance to provide vision on Nyx Assassin to her and her team.
Additional:
* Even though Nyx Assassin can easily kill Luna with his high burst damage, Luna can also do the same to him if he is not careful.
* Lucent Beam can deal a fair amount of damage to Nyx Assassin if he has no Spiked Carapace available to use. Although Luna should be patient using Lucent Beam on Nyx Assassin when he uses Spiked Carapace.
* As Luna commonly buys Black King Bar, she can use it to freely attack Nyx Assassin whenever he tries to defend himself with Spiked Carapace during teamfights. Luna can also buy Eye of Skadi and Manta Style to survive Nyx Assassin's burst damage and distract him.
* Though Vendetta can deal serious damage to Luna and avoid Eclipse, smart Luna will always buy Dust of Appearance to provide vision on Nyx Assassin to her and her team.
Nyx Assassin
* Dragon Knight's heavy armor negates Vendetta's burst physical damage. His large HP pool also gives him a good chance of surviving Nyx Assassin's follow-up nuke damage.
Phoenix
* As a hero with uncommon traits, Phoenix's abilities require more health than mana. It is advised for Rubick to purchase health regeneration items such as 
Tranquil Boots, 
Urn of Shadows or 
Hood of Defiance to keep up with the HP loss.
* Phoenix's signature Supernova, if casted successfully, can turn a teamfight around if being stolen.
* The initial lift and the following crowd control from the drop of 
Telekinesis can protect the egg from being attacked if casted right before Supernova with quick fingers.
* A successfully reborn Supernova refreshes the cooldown of Telekinesis as well as 
Fade Bolt, so don't hesitate to spam both of them before Supernova with the reasons mentioned above.
* Supernova has a stun range of 1200, which requires Rubick to have Level 3 
Arcane Supremacy at least to exceed its range. Consider buying 
Aether Lens or Blink Dagger to help with positioning.
* It is not possible to cast Supernova (as of 7.31c) with Aghanim's Shard's extra 
Sun Ray even with both spell stolen, since Sun Ray takes up two stolen ability slots.
* Icarus Dive is a useful repositioning ability for scouting, initiation or escaping.
* Fire Spirits aids with Rubick farming given enough HP regeneration. In early skirmishes, the stolen ability can slow the attack speed of the enemy team to a crawl.
* Combined with Fade Bolt, both the attack damage and attack speed of the enemy team are reduced if they have no source of dispel, effectively nullifying their physical attack damage.
* Sun Ray thrives in and after a teamfight by damaging enemy heroes and healing allies at the same time.
* Rubick can interrupt both Icarus Dive and Sun Ray by casting Telekinesis.
Phoenix
* Inner Beast helps Beastmaster's team destroy Supernova quickly.
Nyx Assassin
* Nyx Assassin's skillset is mostly single-targeted, therefore he will have difficulties against heroes with illusions and summons: 
Naga Siren, Broodmother, Lycan, 
Visage, Phantom Lancer. And to make things worse, Nyx Asassin is not a common 
Battle Fury, 
Maelstrom, 
Mjollnir, 
Gleipnir or 
Radiance wielder to counter this problem.
Phoenix
* 
Song of the Siren does not affect Supernova, which allows her and her team to focus the egg while the enemy team is affected by sleep.
* Phoenix cannot use Icarus Dive for escaping when rooted by 
Ensnare.
* However, Phoenix has many area-of-effect abilities that allow him to clear Naga Siren's illusions from 
Mirror Image.
Phoenix
* Sand King and Phoenix have many tools to deal with multiple enemies at once, which will work well against a crowd of illusions.
Nyx Assassin
* A well-timed 
Doom prevents Nyx Assassin escaping with Vendetta and fighting back with Spiked Carapace.
* Doom's high health also allows him to easily shrug off Nyx Assassin's burst damage and fend him off.
Nyx Assassin
* With Aghanim's Scepter, Broodmother will gain access to 
Spinner's Snare, which will allow her to create invisible lines on her webs from 
Spin Web that will root, deal damage over time, and reveal enemy heroes if they unwittingly step on them. This allows Broodmother to keep her allies alerted on heroes who rely on invisibility-themed and movement-themed abilities and items to surprise enemy heroes and disrupt ganking attempts of enemy heroes: Phantom Assassin, Nyx Assassin, Mirana, Bounty Hunter, Templar Assassin, Riki, Spirit Breaker, Anti-Mage, Tusk, 
Ursa, 
Nature's Prophet, Enigma, 
Void Spirit, Magnus etc.
Nyx Assassin
* Heroes who rely on damage over time as Spiked Carapace can block and reflect only one instance of damage: Jakiro, Viper, Venomancer, Huskar, Ember Spirit, Dark Seer, Sand King, Doom, Dawnbreaker. However, this also means they are easily stunned.
Nyx Assassin
* Heroes who rely on damage over time as Spiked Carapace can block and reflect only one instance of damage: Jakiro, Viper, Venomancer, Huskar, Ember Spirit, Dark Seer, Sand King, Doom, Dawnbreaker. However, this also means they are easily stunned.
Phoenix
* 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.
Phoenix
* Any hero with high attack speed will be a threat to Phoenix when it initiates, as they can easily tear down a Supernova, perhaps even while debuffed by Fire Spirits: Juggernaut, Clinkz, Troll Warlord, Beastmaster, Lina.
Nyx Assassin
* Heroes who rely on damage over time as Spiked Carapace can block and reflect only one instance of damage: Jakiro, Viper, Venomancer, Huskar, Ember Spirit, Dark Seer, Sand King, Doom, Dawnbreaker. However, this also means they are easily stunned.
Nyx Assassin
* Some abilities deals damage from an independent source and not from the hero itself, so Nyx cannot counter them with Spiked Carapace: illusions or summoning units, 
Homing Missile, 
Nimbus, 
Mass Serpent Ward, 
Death Ward and especially 
Techies's mines.
Nyx Assassin
* Duel's long duration prevents Nyx Assassin escaping from Vendetta. With Aghanim's Scepter, she can also bypass Spiked Carapace.
Phoenix
* Heroes who can hide the Dueled target (
Outworld Destroyer, 
Shadow Demon, Tusk, Phoenix with Aghanim's Scepter etc).
Additional:
* Legion Commander relies on her powerful attack and her 
Duel to be effective. But if Phoenix gets the jump on her first, she can find herself severely slowed, taking heavy damage, and find herself unable to Duel a burning Supernova.
* It must be noted that 
Press the Attack will both dispel the attack slow of Fire Spirits and grant her or whoever she targets bonus attack speed. This allows her to easily destroy a Supernova if caution is not taken to prevent this from occurring. As such, it would be a better decision to simply avoid a farmed or skilled Legion Commander instead of attempting to overpower her.
* If an ally is caught by Duel, Phoenix can use Sun Ray to heal the ally and damage Legion Commander, possibly swinging the Duel in their team's favor. Or with Aghanim's Scepter, Phoenix can save an ally from dying in Duel with Supernova and cancel the Duel as well.
Phoenix
* Phoenix's limit AoE, damage-over-time abilities give Io plenty of time to save allies with Relocate.
Nyx Assassin
* Heroes with either magical, physical or pure damage burst: 
Bane, Ember Spirit, 
Leshrac, Lina, Luna, Nyx Assassin, Phantom Assassin, Skywrath Mage, 
Tinker, Ursa, Void Spirit.
Nyx Assassin
* Heroes who build Black King Bar as either core or situational item will be able to fight back against Nyx Assassin and freely attack him as Spiked Carapace cannot pierce spell immunity at all: Axe, Broodmother, Dawnbreaker, Enigma, Huskar, Jakiro, Legion Commander, Lina, Luna, Lycan, Slardar, Slark, Troll Warlord, Witch Doctor.
Phoenix
* Any hero with high attack speed will be a threat to Phoenix when it initiates, as they can easily tear down a Supernova, perhaps even while debuffed by Fire Spirits: Juggernaut, Clinkz, Troll Warlord, Beastmaster, Lina.
Nyx Assassin
* Mind Flare does tons of damage against Lina because of her high intelligence.
* Vendetta can deal heavy damage to Lina while also burning her mana, preventing Lina from casting her abilities.
* 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. However, Lina can counter this with 
Eul's Scepter of Divinity, a common item on Lina.
Nyx Assassin
* Heroes with either magical, physical or pure damage burst can often kill Chen or his allies before he can use Hand of God: Lina, Luna, Techies, Shadow Fiend, 
Pugna, Nyx Assassin.
Phoenix
* Phoenix's large damage over time with Icarus Dive and Fire Spirits can kill Chen's allies before he can use Hand of God.
* Phoenix naturally buys 
Spirit Vessel, which allows him to reduce healing from 
Divine Favor and 
Hand of God.
* Phoenix's Supernova cannot be damaged by Chen's creeps, and their normal speed means they will often not be able to kill Phoenix whenever he uses Supernova.
Additional:
* Not only Phoenix is able to disrupt Chen's jungling with Fire Spirits, but its high damage over time can also force Chen to use Hand of God prematurely, potentially wasting any chance to save his allies during teamfights.
* Creeps' damage and attack speed are very abysmal, so Chen often cannot kill Phoenix whenever it casts Supernova.
Nyx Assassin
* Like above, supports with reliable stuns can be a massive problem and force Black King Bar in fights unideally, such as 
Shadow Shaman, 
Lion, Nyx Assassin.
Phoenix
* Primal Beast is disarmed during Trample so will be unable to destroy a Supernova no matter how close it is to him.
* The same ability can also be used to save allies with the help of an Aghanim's Scepter.
* Sun Ray will do thousands of damage to Primal Beast if surviving a full channel time due to his high health scaling for the ability.
* Icarus Dive is a fantastic way to escape Primal Beast after he has used Onslaught.
* Phoenix has a naturally very high health pool making it hard for Primal Beast to deal with him with his magical damage.
Nyx Assassin
* Impale and Spiked Carapace can be used to cancel Dismember easily, and can even do so when Pudge uses it on Nyx Assassin, if timed correctly.
Phoenix
* Heroes with high health especially Strength heroes will take more damage on Sun Ray: Axe, Pudge, Bristleback, 
Mars.
Nyx Assassin
* 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 either 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:
* Spiked 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.
Phoenix
* Heroes with slow movement speeds and small health pools (supports like 
Crystal Maiden or Witch Doctor) are easy targets for Phoenix. Should they be inflicted by its DOT debuffs, they will be very quickly killed without even getting a chance to fight back.
Nyx Assassin
* Heroes with heavy early and mid-game magical damage are also problematic for Phantom Assassin due to being able to easily kill her before she can gain an item advantage over them: Lina, 
Necrophos, Nyx Assassin, 
Gyrocopter, Jakiro, Death Prophet.
Phoenix
* Fire Spirits applies a severe attack speed slow, severely hindering Phantom Assassin's damage output.
* Phantom Assassin cannot cast Phantom Strike on Phoenix during Supernova.
Additional:
* While her 
Phantom Strike does give limited extra attack speed, she cannot use the ability against the Phoenix Sun, and while her 
Blur may protect her from attacks, Phoenix's strong magical DPS burns away her small health pool quickly, and the attack speed slow makes her unable to fight back (provided she has no source of spell immunity).
Nyx Assassin
* Nyx Assassin has a lot of burst damage from his Impale, Mind Flare, 
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.
* However, 
Gust is extremely dangerous for Nyx Assassin, as it's silence can render Nyx Assassin unable to lock down Drow Ranger. And if Gust hits Nyx Assassin while he is invisible with Vendetta, Drow Ranger will be able to detect him and foil his ganking attempts on her because Gust reveals invisible units.
Phoenix
* Heroes who depend on attacks (such as Shadow Fiend or 
Drow Ranger) can be nullified by Fire Spirits' attack speed slow.
Nyx Assassin
* Large area-of-effect with delay or require channeling: Enigma, Crystal Maiden, 
Invoker, Shadow Fiend, Pugna, 
Keeper of the Light, Dawnbreaker.
Phoenix
* Heroes who depend on attacks (such as Shadow Fiend or Drow Ranger) can be nullified by Fire Spirits' attack speed slow.
Nyx Assassin
* Heroes that can pick you off: Clinkz, Nyx Assassin, Puck, Riki.
Phoenix
* Phoenix with Supernova
* Heroes that can dodge Glimpse:
* Puck with 
Phase Shift
* Riki with 
Tricks of the Trade
* Phantom Lancer with 
Doppelganger
* Ember Spirit with 
Sleight of Fist and 
Activate Fire Remnant
* Chaos Knight with 
Phantasm
* Naga Siren with Mirror Image
* Tusk with 
Snowball
* Juggernaut with Omnislash
* 
Brewmaster with Primal Split
* Lifestealer with Infest
* Phoenix with Supernova
Nyx Assassin
* Many of Nyx Assassin's abilities are good against Windranger.
* Impale is great for stunning Windranger and allowing additional disables to be landed.
* Mind Flare is useful against Windranger's decent intelligence growth.
* 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.
Nyx Assassin
* Nyx can walk into Firefly with Spiked Carapace and stun Batrider if he has no Spell Immunity, even if Batrider is focusing on other enemy hero.
Nyx Assassin
* Vendetta can deal great damage against her. However, it requires an direct attack, so Nyx Assassin may have difficulties applying Vendetta on her.
* Enchantress's lack of mobility makes her a primary target for ganking with Vendetta.
* Mind Flare can deal a great damage against her due to being an Intelligence hero.
* Spiked Carapace can reflect Impetus and stun Enchantress.
Additional:
* Spiked Carapace reflects the damage from 
Impetus.
* Enchantress is a rather squishy hero, making her fall easily to Nyx Assassin's high burst damage.
Nyx Assassin
* Nyx's Spiked Carapace can reflect the damage of 
Sharpshooter, instantly killing hoodwink. Nyx can also use Vendetta to position himself in such a way to screen allies from Sharpshooter and catch Hoodwink by surprise.
Phoenix
* Icarus Dive and Supernova can destroy the tree Monkey King is standing on.
* Fire Spirits reduces Monkey King's attack speed, preventing Monkey King from building up Jingu Mastery.
* Supernova can be casted next to Wukong's Command, forcing Monkey King to step away of it or to withstand its massive AOE damage
Additional:
* Icarus Dive, Sun Ray, and Supernova all destroy trees that Monkey King relies on to use his ability 
Tree Dance. If you spot him, you can quickly Icarus Dive in his direction and then follow up with Fire Spirits and Supernova. If you manage to cut the tree he is on, he will be stunned for 4 seconds and will be forced to take a lot of damage. However, most Monkey King players tend to build attack speed items to make use of their passive, 
Jingu Mastery, so a battle against a farmed Monkey King will depend on who gets the jump on the other first.
Phoenix
* Her 
Refraction charges can and will be easily burned away by Phoenix's damage over time abilities, and 
Meld can't protect her from Phoenix's AoE abilities, even without detection.
Additional:
* Phoenix's abilities target and deals damage over time, making them a threat against Meld and Refraction. His abilities' nature makes them pretty hard to correctly land on the target, but that is not a problem against a Templar Assassin that needs to stand still during Meld.
* Icarus Dive allows Phoenix to shrug off the slow from her trap and make an easy escape from her ambush.
* As Templar Assassin relies on her quality-over-quantity bursting attacks to make quick work on fragile target, Fire Spirits' attack speed reduction can cripple her ability to deals any damage during combat. With the debuff applied in early-mid game, a Meld-breaking hit from her is significantly slowed to the point that her target can travel a safe distance before she even lands the hit.
* Sun Ray has a quick damage tick and will burn through her Refraction in no time.
* Supernova deals damage over time in an incredibly large area, and again with her quality-over-quantity style, she may not be able to attack quickly enough to break through the Phoenix Sun by herself. (not to mention the debuff from Fire Spirits) This can lead to a failed ganking attempt or even a turnaround.
Nyx Assassin
* 
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.
Nyx Assassin
* Nyx Assassin's high burst damage, excellent ganking potential and multiple disables pose a threat to Muerta at all stages of the game.
* Mind Flare allows Nyx Assassin to take advantage of Muerta's high intelligence and make a short work of her low health.
* Spiked Carapace and Vendetta allow Nyx to escape or initiate well against Muerta's low mobility.
* As with most retaliation based abilities, Spiked Carapace can easily take advantage of 
Gunslinger's stray shots.
* However, Muerta is a natural Black King Bar wielder. And if she succeeds to activate it before Nyx Assassin can ambush her, he will go down very quickly against Muerta as Spiked Carapace cannot pierce through debuff immunity at all.
Nyx Assassin
* 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.
Nyx Assassin
* Nyx Assassin deals large amounts of pure damage with Vendetta and magical damage with Impale and Mind Flare, allowing him to ignore Terrorblade's armor and burst his low health pool down before he can use 
Sunder.
* Nyx Assassin commonly buys Urn of Shadows, Dagon and 
Meteor Hammer which deal magic damage that ignore Terrorblade's armor.
* However, Terrorblade is a natural Eye of Skadi and Black King Bar wielder, and once he gets those items, Nyx Assassin's solo kill potential against Terrorblade will be gone.
Phoenix
* Supernova negates Kunkka's combo entirely, as it can't be affected by spells while using Supernova.
* Icarus Dive also allows Phoenix to dodge Ghostship and Torrent.
Phoenix
* Phoenix will usually be on the sidelines or further back ready to use Sun Ray. Even after Magnus successfully uses Reverse Polarity and skewer Phoenix's teammates, Phoenix can usually counter-initiate using all of its abilities.
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.
Nyx Assassin
* 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.
Nyx Assassin
* Mana Burn removes much-needed mana for 
Ball Lightning.
* Spiked Carapace triggers on 
Static Remnant for an easy stun.
Additional:
* Vendetta 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.
Nyx Assassin
* 
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.
Additional:
* 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. Mind Flare 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.
Nyx Assassin
* Nyx Assassin can simply activate Spiked Carapace while under many Invoker's abilities to stun him.
* Nyx Assassin takes advantage of Invoker's massive intelligence gain to do tons of damage using Mind Flare, as the spell does more damage based on the target's intelligence.
* Vendetta burns a large amount of Invoker's essential mana pool.
Nyx Assassin
* Nyx Assassin's Spiked Carapace will stun Leshrac when hit by any of his AOE abilities.
* Mind Flare deals high damage due to Leshrac's high intelligence gain.
* Vendetta burns a large amount of Leshrac's essential mana pool.
Nyx Assassin
* 
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.
Additional:
* Nyx Assassin's whole skillset is good against Tinker:
* Impale prevents Tinker from blinding Nyx Assassin or fighting back, while giving Nyx' allies time to catch up to Tinker's position.
* Mind Flare 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.
Phoenix
* Icarus Dive quickly escapes from Shadow Demon abilities, especially 
Demonic Purge.
* Phoenix AoE abilities remove Shadow Demon's illusions created by 
Disruption.
Phoenix
* Supernova allows Phoenix to save himself (or an ally, with Aghanim's Scepter) through 
Echo Slam. Earthshaker will also have a difficult time destroying the supernova, due to his low base attack time and poor agility.
* Icarus Dive can pass through Earthshaker's 
Fissure.
* Most of Phoenix's abilities disable Earthshaker's Blink Dagger for a good period of time due to the damage-over-time nature of its spells.
Nyx Assassin
* Impale and Spiked Carapace interrupts Upheaval with ease.
* Warlock's low health pool, mobility, and high intelligence gain makes him a prime target for Nyx Assassin's burst damage.
Phoenix
* Since all of Phoenix's abilities (except for Supernova) have health costs, heroes like 
Ancient Apparition or Necrophos can turn Phoenix's abilities against it. However, Supernova does completely protect Phoenix from 
Ice Blast.
Nyx Assassin
* 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.
Phoenix
* Icarus Dive helps Phoenix escape from Cold Feet.
* However, all of Pheonix's basic abilities do cost health, which can be harmful under the effects of Ice Blast.
* Supernova can save Phoenix from Ice Blast.
Additional:
* Supernova with or without Aghanim's Scepter allows to save ally or himself through Ice Blast.
* Icarus Dive quickly escapes from 
Cold Feet.
Phoenix
* Due to Spirit Breaker's low attack speed, Supernova is problematic for Spirit Breaker to take down, and even more so with Fire Spirits debuff applied.
Nyx Assassin
* 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.
* Keeper of the Light is very squishy and will very quickly die to Vendetta and it's followup abilities.
Nyx Assassin
* Vendetta disables Vengeance Aura and allows him to attack Vengeful Spirit with Impale and Mind Flare.
* Spiked Carapace is easy to use against a Wave of Terror or Magic Missile.
Nyx Assassin
* Outworld Destroyer'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 Destroyer 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 and/or well timed Spiked Carapace can deal a lot of damage to Outworld Destroyer and stun him, unless Outworld Destroyer used Black King Bar beforehand.
Additional:
* Outworld Destroyer's high intelligence makes him a good target for Mind Flare.
* If timed correctly, Spiked Carapace will return the full damage from Sanity's Eclipse back to Outworld Destroyer. 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.
Nyx Assassin
* Ravage's travel time allows Nyx Assassin to easily stun Tidehunter with Spiked Carapace.
* Vendetta can instantly deplete Tidehunter's low mana pool, especially in the early game, potentially preventing Tidehunter from casting Ravage.
Phoenix
* Clockwerk being confined in his own Power Cogs means Clockwerk is unable to quickly escape from Phoenix's Sun Ray and Supernova.
* Sun Ray will also heal the enemy Clockwerk is fighting, making it unlikely for Clockwerk to take an enemy down with him.
* For the same reasons, Phoenix also makes a powerful ally for Clockwerk when the situation is reversed.
Phoenix
* Lone druid's bear attacks on Phoenix's Supernova Egg don't increase the hit count. Given that Lone Druid's main hero often doesn't have much farm, the Supernova Egg is less likely to get killed.
Nyx Assassin
* Vendetta burns a significant amount of mana on hit, and the damage from the ability drains Medusa's mana pool even further.
* 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.
Additional:
* 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.
Nyx Assassin
* Heroes with invisibility: (Riki, Clinkz, Nyx Assassin.
Phoenix
* Heroes with high health especially Strength heroes will take more damage on Sun Ray: Axe, Pudge, Bristleback, Mars.
Phoenix
* Heroes with strong area damage to destroy Phantasm illusions: Axe, Ember Spirit, Legion Commander, Phoenix
Phoenix
* Heroes with high health especially Strength heroes will take more damage on Sun Ray: Axe, Pudge, Bristleback, Mars.
Phoenix
* Heroes that are able to slow Tiny's attack speed, like Tusk and Phoenix, will greatly limit his Physical damage output.
Nyx Assassin
* Heroes who can drain mana can make Omniknight useless after he uses one or two abilities: Lion, Anti-Mage, Nyx Assassin.
Nyx Assassin
* Nyx Assassin, Bounty Hunter and Slark can all sneak up and kill Shadow Shaman, Nyx being particularly deadly. Shadow Shaman must watch out for Slark carefully, as he can break either (but not both unless he makes a mistake) of Shadow Shaman's 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 Shadow Shaman from prey to predator.
Nyx Assassin
* Heroes who rely on invisibility, such as Bounty Hunter, Clinkz, Mirana, Nyx Assassin and Riki, as they will be revealed if caught by Chronosphere.
Phoenix
* Fire Spirits does damage over time, preventing Faceless Void from backtracking the full damage with Time Walk.
* Fire Spirits applies a big attack speed slow, stopping Faceless Void from doing many attacks while in Chronosphere.
* Sun Ray can heal allies and damage Faceless Void from outside Chronosphere.
* Supernova can be cast outside of Chronosphere, forcing Faceless Void to step away from it, lest he'll take a lot of damage
Nyx Assassin
* Nyx Assassin's skillset is mostly single-targeted, therefore he will have difficulties against heroes with illusions and summons: Naga Siren, Broodmother, Lycan, Visage, Phantom Lancer. And to make things worse, Nyx Asassin is not a common Battle Fury, Maelstrom, Mjollnir, Gleipnir or Radiance wielder to counter this problem.
Phoenix
* Phoenix's AoE abilities can prove troublesome for Phantom Lancer.
* Fire Spirits dramatically reduces Phantom Lancer and his illusions' attack speed.
* Icarus Dive's movement speed reduction makes retreating difficult.
* Supernova burns away illusions, and is invulnerable to attacks from illusions.
Nyx Assassin
* Heroes who rely on damage over time as Spiked Carapace can block and reflect only one instance of damage: Jakiro, Viper, Venomancer, Huskar, Ember Spirit, Dark Seer, Sand King, Doom, Dawnbreaker. However, this also means they are easily stunned.
Nyx Assassin
* 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.
Additional:
* Spiked Carapace can be easily triggered by 
Flame Guard or Battle Fury, setting up a deadly Impale.
Nyx Assassin
* Heroes who rely on damage over time as Spiked Carapace can block and reflect only one instance of damage: Jakiro, Viper, Venomancer, Huskar, Ember Spirit, Dark Seer, Sand King, Doom, Dawnbreaker. However, this also means they are easily stunned.
Phoenix
* Sand King has nothing to deal with Supernova, as none of his spells are effective.
* The damage-over-time abilities of Phoenix disable Sand King's Blink Dagger very often.
Nyx Assassin
* Heroes who rely on damage over time as Spiked Carapace can block and reflect only one instance of damage: Jakiro, Viper, Venomancer, Huskar, Ember Spirit, Dark Seer, Sand King, Doom, Dawnbreaker. However, this also means they are easily stunned.
Nyx Assassin
* Spiked Carapace can stop Dawnbreaker's Solar Guardian which will eliminate her global presence and limits her movement around the map.
Additional:
* Spiked Carapace interrupts 
Starbreaker before Dawnbreaker has her Aghanim's Shard, as well as 
Solar Guardian during the initial channel, making her ineffective at joining and dealing damage in teamfights.
* The slow projectile and damage over time effect of 
Celestial Hammer makes it easy to stun Dawnbreaker if she attemps to engage or chase.
Phoenix
* 
Lil' Shredder will make quick work of Supernova.
* 
Mortimer Kisses can easily hit a Phoenix using Sun Ray.
Nyx Assassin
* Spiked Carapace stops Snapfire's Mortimer Kisses.
Nyx Assassin
* Heroes who build Black King Bar as either core or situational item will be able to fight back against Nyx Assassin and freely attack him as Spiked Carapace cannot pierce spell immunity at all: Axe, Broodmother, Dawnbreaker, Enigma, Huskar, Jakiro, Legion Commander, Lina, Luna, Lycan, Slardar, Slark, Troll Warlord, Witch Doctor.
Phoenix
* Heroes with slow movement speeds and small health pools (supports like Crystal Maiden or Witch Doctor) are easy targets for Phoenix. Should they be inflicted by its DOT debuffs, they will be very quickly killed without even getting a chance to fight back.
Phoenix
* 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.
Nyx Assassin
* Slow-moving projectiles: Skywrath Mage, Tinker, Necrophos
Additional:
* 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.
* Mind Flare turns Skywrath Mage's high intelligence growth against him and deals heavy damage.
* Spiked Carapace gives Nyx some degree of protection against Skywrath's spells.
Nyx Assassin
* 
Corrosive Haze hinders Nyx Assassin's ganking attempts with Vendetta, as well as reducing his armor and make him very vulnerable due to his low health pool.
* 
Guardian Sprint allows Slardar to catch up with Nyx Asssassin and finish him off if he has vision over him.
Phoenix
* Fire Spirits greatly reduces Slardar's already low starting attack speed (which Bash of the Deep relies on), making the laning phase very hard for him and discouraging Slardar from aggressively threatening lane kills.
* Supernova, ignoring Phoenix's lack of armor and Slardar's high damage single hits, is extremely hard for Slardar to take down on his own, especially after being hit by Fire Spirits.
* Icarus Dive is one of the longest distance escape spells in the game, and can help a good Phoenix escape from Slardar before he gets a Blink Dagger. However, the high cooldown means Phoenix is vulnerable to backstabs from any roamers after said spell is used.
* Slardar can interrupt an Icarus Dive from completing the flight with both of his stuns, however, likely leading to death if Supernova is on cooldown.
* A lot of the items a Phoenix builds throughout the game naturally counter Slardar. 
Shiva's Guard, 
Heaven's Halberd and Eul's Scepter of Divinity all stall Slardar's normal attacks in some way, while Spirit Vessel's percentage-based damage is good against his innate durability.
Phoenix
* Although Phoenix has many ways to disable a Blink Dagger, the high cooldown of all of its spells makes them not as reliable for this. Also, its spells cost a lot of health to use, making it easy to get nuked down.
* Waning Rift prevents Phoenix from using Supernova to refresh itself, giving Puck's team time to finish it off, or allow Puck to burst Phoenix down.
* Dream Coil prevents Phoenix from using Icarus Dive without consequences. Waning Rift and Dream Coil are also able to cancel Sun Ray, which is its main source of damage in the late game.
Nyx Assassin
* 
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.
Additional:
* 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 Mind Flare that much more deadly against Puck.
* An ill-timed Phase Shift can turn into an easy setup for Impale.
Phoenix
* Phoenix constantly depletes its own health due to the health costs of its abilities. Unlike heroes that have a similar mechanic, Phoenix does not benefit from low health, nor does it really have a countermeasure for it. As such, Phoenix is a very vulnerable target for Necrophos to prey on, especially when caught off guard before it can cast Supernova.
Additional:
* Necrophos becomes a bigger threat the lower one's health gets, and unfortunately for Phoenix, most of its spells have noticeable health costs. Those costs, coupled with his 
Heartstopper Aura, means that staying in a teamfight for too long under Necrophos' presence will make Phoenix a more valid target for his ultimate, with its stun completely preventing any form of retaliation or protection. Necrophos players are also likely to buy more durability items such as Hood of Defiance, making him more able to withstand Phoenix's damage despite having no escape mechanisms.
* However, it is also important to remember that a Scepter-upgraded Supernova can help protect an ally from his ultimate.
Nyx Assassin
* 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 Mind Flare or Impale.
Nyx Assassin
* Heroes who are entirely reliant on dealing physical damage and/or have very little to no area-of-effect abilities will make Underlord tickle and will have no effect against him thanks to his 
Atrophy Aura, and will also be unable to ambush Underlord and his team if Underlord chooses to use 
Fiend's Gate to get to a designated point of the map: Phantom Assassin, 
Terrorblade, Troll Warlord, Drow Ranger, Phantom Lancer, Chaos Knight, 
Sven, 
Wraith King, Bounty Hunter, 
Alchemist, Templar Assassin, Nyx Assassin, Bane.
Nyx Assassin
* Heroes with magical or pure damage output will not have any problems against Atrophy Aura at all: Luna, Lina, Jakiro, Pugna, Bane, 
Snapfire, 
Muerta, Nyx Assassin, Enigma, Tinker, Witch Doctor, 
Zeus, Crystal Maiden.
Nyx Assassin
* Heroes who build Black King Bar as either core or situational item will be able to fight back against Nyx Assassin and freely attack him as Spiked Carapace cannot pierce spell immunity at all: Axe, Broodmother, Dawnbreaker, Enigma, Huskar, Jakiro, Legion Commander, Lina, Luna, Lycan, Slardar, Slark, Troll Warlord, Witch Doctor.
Nyx Assassin
* 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, Luna, 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.
Phoenix
* Heroes that depend on disrupting fights with ability combos or big ultimate abilities are vulnerable to the long stun of Fiend's Grip: 
Disruptor, Death Prophet, Enigma, Faceless Void, Invoker, 
Lich, Magnus, Mars, Medusa, Outworld Destroyer, Phoenix, Puck, Queen of Pain, Shadow Fiend, Treant Protector, 
Underlord, 
Winter Wyvern, Witch Doctor, Zeus.
Phoenix
* Heroes with hiding abilities can protect disabled allies: Outworld Destroyer, Shadow Demon, Tusk, Phoenix with Aghanim's Scepter.
Phoenix
* Silencer will most likely disrupt an initiation with his ultimate, 
Global Silence, prevent escape with his 
Last Word, and if Phoenix happens to die to him (or near him) enough times, he would sap enough of Phoenix's much needed Intelligence to make him a stronger foe and Phoenix with less mana than it already had.
Nyx Assassin
* Last Word is extremely easy to reflect with Spiked Carapace for large amounts damage, due to triggering when Nyx Assassin casts a spell, but can still silence Nyx Assassin. It also has the added bonus of dealing more damage the more Intelligence Silencer has.
* 
Glaives of Wisdom quickly builds Silencer's Intelligence, making him a particularly prime target for Mana Burn.
* Silencer rarely builds survivability items, nor is he able to steal much Intelligence while surrounded by his team, and so is an excellent target for Vendetta.
* Silencer has no reliable way of dealing with a burrowed Nyx, and also lacks the ability to prevent Nyx from escaping with Vendetta,
Additional:
* Silencer is rather squishy and has poor mobility without items, making him an easy target for Nyx.
* Silencer's intelligence steal ability is a complete disadvantage against Nyx Assassin as Mind Flare will deal increasing damage for each point of intelligence Silencer has stolen, turning Silencer's intelligence steal against him.
Nyx Assassin
* A well-timed 
Berserker's Call can expose Nyx Assassin while he is invisible with Vendetta, and prevent him from using Spiked Carapace.
* Axe can use 
Battle Hunger's damage over time to minimialize effects of Spiked Carapace.
* Axe's high health also allows him to easily shrug off Nyx Assassin's burst damage and fend him off. Especially since Axe is a common 
Heart of Tarrasque wielder, which can completely eliminate any chance for Nyx Assassin to kill Axe alone.
* 
Culling Blade can often kill Nyx Assassin as he is very fragile and vulnerable to damage while Spiked Carapace is on cooldown.
Additional:
* A well-timed Berserker's Call can expose Nyx Assassin while he is invisible with Vendetta, and prevent him from using Spiked Carapace.
* Axe can use Battle Hunger's damage over time to minimialize effects of Spiked Carapace.
* Axe's high health also allows him to easily shrug off Nyx Assassin's burst damage and fend him off. Especially since Axe is a common Heart of Tarrasque wielder, which can completely eliminate any chance for Nyx Assassin to kill Axe alone.
* Culling Blade can often kill Nyx Assassin as he is very fragile and vulnerable to damage while Spiked Carapace is on cooldown.
Phoenix
* Sun Ray allows Phoenix to heal any allies caught in Berserker's Call while burning away Axe's high HP at the same time.
* Icarus Dive and Fire Spirits puts Axe's Blink Dagger on cooldown.
* Axe's slow attack speed makes it difficult for him to destroy Supernova on his own.
Nyx Assassin
* Even though Visage's Familiars from 
Summon Familiars are fragile and can be killed quickly with Nyx Assassin's high burst damage, they can deal many instances of damage quickly, minimizing the effectiveness of Spiked Carapace.
* 
Gravekeeper's Cloak and tanky item builds make Visage hard for Nyx to kill with his burst damage. Aghanim's Shard upgraded Gravekeeper's Cloak also allows Visage to use 
Stone Form to both recover himself and stun Nyx Assassin if he is close enough to Visage.
* Visage's long range on 
Soul Assumption and 
Grave Chill make him hard to escape from, and Soul Assumption's low cooldown outmatches Spiked Carapace.
Phoenix
* Phoenix's Supernova cannot be damaged by Familiars.
* In the early and mid game, Sun Ray won't deal enough damage to be reduced by Gravekeeper's Cloak.
* Once Sun Ray deals enough damage to protect Visage, a layer of Gravekeeper's Cloak is burnt every 0.2 seconds.
Nyx Assassin
*
Blade Fury makes Juggernaut immune to all Nyx's abilities, except 
Vendetta.
Omnislash. and 
Swiftslash can burst Nyx down, ignoring 
Spiked Carapace. However, 
Vendetta can be used to escape, canceling 
Omnislash/
Swiftslash.
Spiked Carapace, his most important ability.
Blade Fury allows Juggernaut to freely attack Nyx Assassin, and deal heavy damage to Nyx Assassin. Nyx Assassin cannot counter 
Blade Fury with Spiked Carapace because 
Blade Fury gives Juggernaut spell immunity. And besides 
Vendetta, Nyx Assassin has no other way of dealing damage to Juggernaut while he is spell immune.
Healing Ward allows Juggernaut to recover himself and his allies from Nyx Assassin's damage output.
Omnislash and 
Swiftslash from 
Aghanim's Scepter can quickly finish off Nyx Assassin. And just like 
Blade Fury, Nyx Assassin cannot counter neither 
Omnislash and 
Swiftslash from 
Aghanim's Scepter with 
Spiked Carapace because both abilities render Juggernaut invulnerable. And if Nyx Assassin has no Vendetta available to use for escaping, both abilities will kill him very quickly before he can do anything.
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Additional:
* Juggernaut's entire skillset greatly counters Nyx Assassin's
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* Overall, any attempt for Nyx Assassin to gank and kill Juggernaut will hurt Nyx Assassin more than Juggernaut.
Phoenix
* Juggernaut's high attack speed lets him destroy a
Supernova easily. He can even attack a Supernova during Blade Fury with his regular attacks.
Blade Fury protects Juggernaut from all of Phoenix's spells (except 
Supernova, which pierces spell immunity).
Blade Fury can also dispel the attack speed slow from 
Fire Spirits and the movement speed slow from 
Icarus Dive.
Icarus Dive will not protect it from 
Omnislash unless it dives into creeps, and Phoenix's low armor makes for an easy kill.
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* Phoenix's