Shadow Fiend
* 
Lucent Beam and 
Eclipse with ministun talent can be used to cancel Requiem of Souls if Shadow Fiend does not have 
Black King Bar. Likewise, since Shadow Fiend is prone to buying 
Blink Dagger, an ill-timed Blink Dagger can give Luna a free chance to counter-initiate with Eclipse.
* 
Moon Glaives and 
Lunar Blessing allow Luna to outfarm Shadow Fiend in lane and the high physical damage output they provide her can also help her deal with Shadow Fiend even when he buys Black King Bar in late game.
* A well timed Eclipse will burst and kill Shadow Fiend before he even either initiates or gets a chance to retaliate, especially when equipped with 
Aghanim's Scepter and 
Ethereal Blade, this could become even worse for Shadow Fiend if he does not have Black King Bar. But bear in mind however, that smart and skilled Shadow Fiend can buy 
Wind Waker to counter this issue.
* Even though Shadow Fiend can evade all of Luna's abilities with 
Shadow Blade, smart Luna will always buy 
Dust of Appearance to provide vision on Shadow Fiend to her and her team.
Additional:
* Lucent Beam and Eclipse with ministun talent can be used to cancel Requiem of Souls if Shadow Fiend does not have Black King Bar. Likewise, since Shadow Fiend is prone to buying Blink Dagger, an ill-timed Blink Dagger can give Luna a free chance to counter-initiate with Eclipse.
* Moon Glaives and Lunar Blessing allow Luna to outfarm Shadow Fiend in lane and the high physical damage output they provide her can also help her deal with Shadow Fiend even when he buys Black King Bar in late game.
* A well timed Eclipse will burst and kill Shadow Fiend before he even either initiates or gets a chance to retaliate, especially when equipped with Aghanim's Scepter and Ethereal Blade, this could become even worse for Shadow Fiend if he does not have Black King Bar. But bear in mind however, that smart and skilled Shadow Fiend can buy Wind Waker to counter this issue.
* Even though Shadow Fiend can evade all of Luna's abilities with Shadow Blade, a smart Luna will always buy Dust of Appearance to provide vision on Shadow Fiend to her and her team.
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.
Shadow Fiend
* Bounty Hunter can absolutely destroy a Shadow Fiend's game by ganking his midlane with Shadow Walk, Jinada and Shuriken Toss.
* If his lane goes bad, a Shadow Fiend usually goes to the jungle. Follow him with Shadow Walk and take half of his experience.
* Due to its ministun, Shuriken Toss is a good way to interrupt Shadow Fiend's long cast animation on 
Requiem of Souls.
Additional:
* 
Shuriken Toss can be used to cancel Requiem of Souls.
* 
Shadow Walk and 
Jinada allow Bounty Hunter to gank Shadow Fiend early on
* 
Track prevents Shadow Fiend from escaping with Shadow Blade.
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 attempts with Vendetta, making him an easy kill for gold as well.
Shadow Fiend
* 
Nethertoxin breaks both Necromastery and Presence of the Dark Lord, reducing his damage massively.
* 
Corrosive Skin gives Viper bonus Magic Resistance against Shadowraze and Requiem of Souls.
* Viper can easily take advantage of Shadow Fiend's lack of escape and mobility spells with 
Viper Strike and 
Poison Attack. Poison Attack also serves as a great way to harass Shadow Fiend.
Nyx Assassin
* Corrosive Skin minimizes the damage from 
Impale and 
Mind Flare.
* Nyx Assassin cannot survive several poison damage-over-time, even Spiked Carapace is activated.
Shadow Fiend
* 
Berserker's Call and 
Counter Helix allow Axe to kill Shadow Fiend if he stands too close to a creep wave.
* 
Battle Hunger is can be strong against Shadow Fiend in the early game because Shadow Fiend's low attack damage makes it hard for him to get last hits if he has no mana. However, Shadowraze also makes it very easy for him to get last hits, so use with caution.
* 
Axe's naturally high strength and health regeneration will be enough to tank a lot of Shadow Fiend's damage in the early game.
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.
Shadow Fiend
* Doom has several disable abilities to choose from jungle creeps (e.g. 
War Stomp, 
Ensnare) to deal with Shadow Fiend who lacks escape abilities.
* When Doom combines creep abilities with 
Scorched Earth, 
Infernal Blade, and 
Doom, Shadow Fiend most likely will die as he cannot use Shadowraze and Requiem of Souls to protect himself, and also cannot even flee by using Shadow Blade or Blink Dagger.
* Although Shadow Fiend has a high physical damage output, Doom has a large health pool to survive it, meaning Doom's combo with high magical damage output will shutdown Shadow Fiend first.
* Doom usually buys 
Radiance to improve his damage, making his nuke combo more deadly to Shadow Fiend. The blind also prevents Shadow Fiend from landing his attacks often.
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.
Shadow Fiend
* Despite Jakiro's fragileness, he can easily harass Shadow Fiend with 
Dual Breath and 
Liquid Fire than Shadow Fiend can harass Jakiro with 
Shadowraze.
* Jakiro can easily cancel Requiem of Souls with 
Ice Path as Shadow Fiend is a very easy target while channeling it.
* Aghanim's Scepter upgraded 
Macropyre can deal pure damage-over-time and pierce spell immunity, which can discourage Shadow Fiend from even trying to initiate with Requiem of Souls.
Additional:
* Despite Jakiro's fragileness, he can easily harass Shadow Fiend with Dual Breath and Liquid Fire than Shadow Fiend can harass Jakiro with Shadowraze.
* Jakiro can easily cancel Requiem of Souls with Ice Path as Shadow Fiend is a very easy target while channeling it.
* Aghanim's Scepter upgraded Macropyre can deal pure damage-over-time and pierce spell immunity, which can discourage Shadow Fiend from even trying to initiate with Requiem of Souls.
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.
Shadow Fiend
* 
Void can be used to cancel Requiem of Souls.
* 
Crippling Fear prevents Shadow Fiend from using Shadowraze or Requiem of Souls.
* With 
Dark Ascension and 
Gem of True Sight, Night Stalker can find and kill Shadow Fiend easily. He is also a tanky hero that can fight Shadow Fiend at any stage of the game.
Nyx Assassin
* Heroes that have a weak laning stage: 
Spectre, 
Nyx Assassin, 
Clockwerk, 
Spirit Breaker, 
Omniknight, 
Pudge.
Shadow Fiend
* 
Dragon Tail can be used to cancel Requiem of Souls.
* 
Breathe Fire reduces Shadow Fiend's damage even further.
* 
Dragon Knight's high strength and 
Dragon Blood means that he'll be able to tank Shadow Fiend's right clicks.
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.
Shadow Fiend
* 
Shadow Fiend's 
Presence of the Dark Lord reduces Dragon Knight's armor considerably, and his strong base attacks are augmented by his 
Necromastery.
Shadow Fiend
* 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
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
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.
Shadow Fiend
* 
Arc Lightning allows Zeus to get farm in lane against Shadow Fiend without coming into the range of his Shadowrazes.
* 
Lightning Bolt can be used to heavily harass Shadow Fiend when he tries to get a last hit.
* 
Thundergod's Wrath and Lightning Bolt can be used to detect Shadow Fiend if he tries to escape with Shadow Blade.
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.
Shadow Fiend
* 
Enfeeble can be used to decrease Shadow Fiend's already abysmal level one damage even further, preventing him from getting farm and Necromastery stacks.
* 
Brain Sap allows Bane to heavily harass Shadow Fiend.
* 
Nightmare allows Bane to set up some early ganks onto Shadow Fiend.
* 
Fiend's Grip enables Bane to completely take Shadow Fiend out of a fight and potentially even kill him, even through Black King Bar.
Additional:
* Enfeeble can be used to decrease Shadow Fiend's already abysmal level one damage even further, preventing him from getting farm and Necromastery stacks.
* Brain Sap allows Bane to heavily harass Shadow Fiend.
* Nightmare allows Bane to set up some early ganks onto Shadow Fiend.
* Fiend's Grip enables Bane to completely take Shadow Fiend out of a fight and potentially even kill him, even through Black King Bar.
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.
Nyx Assassin
* 
Cyclone from Storm in 
Primal Split can waste Nyx's Spiked Carapace, since its duration is shorter than the Cyclone's.
Shadow Fiend
* 
Charge of Darkness allows Spirit Breaker to gank Shadow Fiend in the early game, preventing him from getting Necromastery stacks.
* 
Nether Strike and Charge of Darkness can be used to prevent Shadow Fiend from casting Requiem of Souls.
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.
Additional:
* Juggernaut's entire skillset greatly counters Nyx Assassin's 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.
* Overall, any attempt for Nyx Assassin to gank and kill Juggernaut will hurt Nyx Assassin more than Juggernaut.
Nyx Assassin
* Duel's long duration prevents Nyx Assassin escaping from Vendetta. With Aghanim's Scepter, she can also bypass Spiked Carapace.
Shadow Fiend
* 
Earthshock prevents Shadow Fiend from escaping after Ursa used his Blink Dagger to get on top of him.
* 
Overpower and 
Fury Swipes allow Ursa to quickly kill Shadow Fiend.
* 
Enrage keeps Ursa alive in a manfight with Shadow Fiend and allows him to stay close, even if Shadow Fiend uses Requiem of Souls.
Shadow Fiend
* Shadow Fiend's fragility and lack of a natural escape mechanism makes him a great target for Templar Assassin's Meld.
* Shadow Fiend's burst damage, such as Shadowraze and Requiem of Souls, is easily nullified by her Refraction.
Shadow Fiend
* Requiem of Souls is easily interrupted by Boundless Strike, due to its long cast time.
* Shadow Fiend's lack of mobility and escape makes him an easy target to ambush with Primal Spring, especially during laning stage.
* Being close means he cannot use all three razes on you before you get your Jingu Mastery stacks.
Shadow Fiend
* Shadow Fiend's lack of mobility and low base health make him an easy target for early ganks.
Shadow Fiend
* 
Static Link can steal Shadow Fiend's high physical damage output from Necromastery, lowering his damage output, and Static Link cannot be prevented by Black King Bar.
* 
Plasma Field and 
Eye of the Storm can melt down Shadow Fiend easily, due to his low health.
Shadow Fiend
* Shadow Fiend's Requiem of Souls allows Rubick to output enormous crowd damage and control to the enemy team.
* Requiem of Souls has an effective range of 1000. 
Rubick can steal the spell out of the fear range with any level of 
Arcane Supremacy learned.
* Requiem of Souls has a significant cast animation which allows Rubick to predict the steal timing, since Shadow Fiend usually positions at the center of battlefield.
* 
Telekinesis can lift a unit right on top of Rubick with no collision size, forcing the victim to absorb all damaging lines of Requiem of Souls from Rubick, possibly resulting in a one-shot kill.
* Note that Requiem of Souls from Rubick still uses the original 1.67 second channeling time.
* It is advised to build Blink Dagger to jump in and cast Requiem of Souls given the opportunity.
* The three 
Shadowraze (Far) abilities are decent for farming and extra damage output.
* Note that 
Shadowraze (Near), 
Shadowraze (Medium) and Shadowraze (Far) are considered three separated abilities, only one is stolen per spell steal cast.
* It could be troublesome to cast Shadowraze (Far) immediately for damage output immediately after stolen since it is hard to react and recognize which of the three is stolen.
* Shadow Fiend's right click damage together with his ability damage may hurt Rubick bad. Consider items like 
Ghost Scepter and 
Glimmer Cape, together with wards to avoid being picked up.
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.
Shadow Fiend
* Heroes that can gank Shadow Fiend in the early game: 
Earth Spirit, Nyx Assassin, 
Riki, Spirit Breaker.
Nyx Assassin
* Heroes who rely on damage over time as Spiked Carapace can block and reflect only one instance of damage: 
Venomancer, Huskar, 
Ember Spirit, 
Dark Seer, 
Sand King, 
Doom, Dawnbreaker. However, this also means they are easily stunned.
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
* 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.
Nyx Assassin
* Heroes who rely on damage over time as Spiked Carapace can block and reflect only one instance of damage: Venomancer, Huskar, Ember Spirit, Dark Seer, Sand King, Doom, Dawnbreaker. However, this also means they are easily stunned.
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.
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.
Shadow Fiend
* Outlanes Shadow Fiend on the central line, due to the fact that Lina's attack range exceeds the range of Shadow Fiend, which makes it difficult for him to fend off her attacks and approach creeps, thus Lina has more level and gold
* Defeats Shadow Fiend` from Burst with a combination of skills: 
Light Strike Array, 
Dragon Slave, 
Laguna Blade, Shadow Fiend does not have a large pool of health before buying an item: 
Satanic , which is why Lina's strong magic damage is enough to kill him quickly
Additional:
* Outlanes Shadow Fiend on the central line, due to the fact that Lina's attack range exceeds the range of Shadow Fiend, which makes it difficult for him to fend off her attacks and approach creeps, thus Lina has more level and gold
* Defeats Shadow Fiend` from Burst with a combination of skills: Light Strike Array, Dragon Slave, Laguna Blade, Shadow Fiend does not have a large pool of health before buying an item: Satanic , which is why Lina's strong magic damage is enough to kill him quickly
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
* Mind Flare does tons of damage against Lina because of her high intelligence.
* The mana burn from Vendetta 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
* Heroes who rely on damage over time as Spiked Carapace can block and reflect only one instance of damage: Venomancer, Huskar, Ember Spirit, Dark Seer, Sand King, Doom, Dawnbreaker. However, this also means they are easily stunned.
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, although he can at least partially counter it with a well-timed Spiked Carapace.
* 
Thirst is always a threat to Nyx Assassin, hindering his attempt of escape using Vendetta.
* 
Rupture also prevents Nyx Assassin from escaping with Vendetta, as it forces him to stay still.
Shadow Fiend
* Squishy core heroes (Shadow Fiend, 
Sniper, etc)
Shadow Fiend
* Heroes that can gank Shadow Fiend in the early game: Earth Spirit, Nyx Assassin, Riki, Spirit Breaker.
Shadow Fiend
* Heroes with high physical damage output but lack of reliable escape mechanisms are always a good target for a solo gank: Sniper, Shadow Fiend, Troll Warlord, 
Drow Ranger. Those heroes, however, are dangerous if they manage to close the gap, so take caution.
Shadow Fiend
* Heroes with channeling spells because Shadow Fiend has nothing to cancel channeling outside of Requiem of Souls: 
Bane, Enigma, Pudge, 
Shadow Shaman, Dawnbreaker, 
Warlock, 
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.
Shadow Fiend
* Heroes with high burst damage: Lina, Lion, Luna, Nyx Assassin, 
Queen of Pain.
Shadow Fiend
* Late game heroes are Sven's favourite kind of opponent, such as 
Anti-Mage, Spectre and Shadow Fiend.
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
* 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.
Nyx Assassin
* Nyx Assassin might not kill Abaddon with his nuke, but a support Abaddon will struggle to protect an ally from him.
Nyx Assassin
* 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.
Shadow Fiend
* Heroes with high physical damage can damage Lifestealer more than he can heal: Bristleback, Clinkz, Luna,Shadow Fiend, Slardar, 
Terrorblade
Shadow Fiend
* 
Glimpse and 
Kinetic Field allows Disruptor to set up some early kills onto Shadow Fiend.
* 
Static Storm can be used to cancel the cast of Requiem of Souls.
Nyx Assassin
* Heroes that can pick you off: Clinkz, Nyx Assassin, Puck, Riki.
Shadow Fiend
* Heroes with channeling spells because Shadow Fiend has nothing to cancel channeling outside of Requiem of Souls: Bane, Enigma, Pudge, Shadow Shaman, Dawnbreaker, Warlock, Crystal Maiden.
Nyx Assassin
* Heroes who rely on damage over time as Spiked Carapace can block and reflect only one instance of damage: 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.
Shadow Fiend
* Shadow Fiend is mostly played as right-click carry and natural Black King Bar carrier, making Silencer's spells very ineffective against him.
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.
Shadow Fiend
* Shadow Fiend can easily farm his treants and get easy Necromastery Stacks.
* If Shadow Fiend buys 
Boots of Travel and Shadow Blade, he can counteract Nature's Prophet's split-push.
Nyx Assassin
* Heroes with invisibility: (Riki, Clinkz, Nyx Assassin.
Shadow Fiend
* Shadowraze can clear waves of Chen's creeps while giving Shadow Fiend gold and damage for Necromastery.
* Requiem of Souls's very high magical damage can often kill Chen and his creeps or his allies before he can save them with 
Hand of God.
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.
Nyx Assassin
* Heroes who rely on damage over time as Spiked Carapace can block and reflect only one instance of damage: Venomancer, Huskar, Ember Spirit, Dark Seer, Sand King, Doom, Dawnbreaker. However, this also means they are easily stunned.
Shadow Fiend
* Shadowraze can easily remove the protection from Flame Guard and kill Ember Spirit due to his low health.
* Ember Spirit is very vulnerable to physical damage from Necromastery.
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.
Shadow Fiend
* Heroes with a low health pool (Crystal Maiden, 
Skywrath Mage etc)
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
* 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 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.
Shadow Fiend
* Shadowraze deals magic damage and ignores Bulwark.
* Requiem of Souls deals magic damage and can fear Mars away, forcing him to turn around and therefore become vulnerable.
Nyx Assassin
* Spiked Carapace stops Snapfire's 
Mortimer Kisses.
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
* 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.
Shadow Fiend
* Heroes with channeling spells because Shadow Fiend has nothing to cancel channeling outside of Requiem of Souls: Bane, Enigma, Pudge, Shadow Shaman, Dawnbreaker, Warlock, Crystal Maiden.
Shadow Fiend
* Heroes with a low health pool (Crystal Maiden, Skywrath Mage etc)
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.
Shadow Fiend
* Shadow Fiend usually buys a 
Hurricane Pike allowing him to easily escape from 
Power Cogs.
* Shadow Fiend can farm Clockwerk's Power Cogs to gain Necromastery stacks.
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.
Shadow Fiend
* Shadowraze (Near), Shadowraze (Medium), and Shadowraze (Far) can hit hard in the early stages of the game, and due to Shadow Fiend's high attack damage, most of Death Prophet's last hits will be denied in the laning phase. Additionally, Requiem of Souls can deal massive damage or kill Death Prophet at the start of team fights in combination with 
Eul's Scepter of Divinity or Shadow Blade.
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.
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
* 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.
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 abuses Muerta's high intelligence to make 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.
Shadow Fiend
* Wins on the central line, thanks to its strong nukes Shadowraze, because of which Void Spirit cannot approach the creeps to farm gold and overtake Shadow Fiend by level
Additional:
* Wins on the central line, thanks to its strong nukes Shadowraze, because of which Void Spirit cannot approach the creeps to farm gold and overtake Shadow Fiend by level
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
* 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
* 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.
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.
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
* 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.
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.
Shadow Fiend
* Shadow Fiend's Requiem of Souls not only slow all Meepos, but it can also kill the weakest Meepo instantly if the ultimate is released at the right position and time.
Additional:
* Shadow Fiend can easily focus down and kill one of the Meepos.
* The amount of damage from Shadow Fiend's AoE spells makes Meepo vulnerable in every aspect.
Shadow Fiend
* Squishy heroes or heroes without hard disables or silences: 
Shadow Demon, Shadow Fiend, Venomancer, 
Ancient Apparition etc.
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
* In general, attacks of the melee 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, and will 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.
Shadow Fiend
* Shadow Fiend can still dish out heavy damage with Requiem of Souls and Shadowraze while caught in Pit of Malice.
Shadow Fiend
* Heroes that are hard to kill without lockdown: Puck, Weaver.
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.
Shadow Fiend
* Heroes with channeling spells because Shadow Fiend has nothing to cancel channeling outside of Requiem of Souls: Bane, Enigma, Pudge, Shadow Shaman, Dawnbreaker, Warlock, Crystal Maiden.
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.
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.
Shadow Fiend
* 
Shadow Dance does not protect Slark from Shadow Fiend's AoE spells.
Shadow Fiend
* Heroes with high burst damage: Lina, Lion, Luna, Nyx Assassin, Queen of Pain.
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.
Shadow Fiend
* Heroes with long animations can be frequently interrupted with Cold Snap: 
Earthshaker, 
Monkey King, Shadow Fiend Lina
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.
Shadow Fiend
* Heroes that are hard to kill without lockdown: Puck, Weaver.
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.
Shadow Fiend
* Heroes who depend on attacks (such as Shadow Fiend or Drow Ranger) can be nullified by Fire Spirits' attack speed slow.
Nyx Assassin
* Spiked Carapace reacts on any of the damage over time from Phoenix's abilities and can interrupt 
Sun Ray and 
Icarus Dive.
Shadow Fiend
* Heroes with channeling spells because Shadow Fiend has nothing to cancel channeling outside of Requiem of Souls: Bane, Enigma, Pudge, Shadow Shaman, Dawnbreaker, Warlock, Crystal Maiden.
Additional:
* Because Shadow Fiend lacks escaping mechanisms, and is dependent on fair positioning for channeling Requiem of Souls, it's easier for Warlock with his long range crowd control abilities to lock Shadow Fiend down for his team.
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.
Shadow Fiend
* Heroes that have small health pools and little to no escape mechanisms are even easier prey for Necrophos. Ghost Shroud's slow will allow him to catch him with them, and get nuked down with his abilities, even preventing retaliation due to Reaper's Scythe's stun. Such heroes include Crystal Maiden, Witch Doctor, Warlock or Shadow Fiend.
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 with very little to no area-of-effect abilities will struggle greatly against Broodmother: Sniper, Phantom Assassin, Nyx Assassin, Bane, Visage, Bounty Hunter.
Shadow Fiend
* Spiderlings are a good source of farm for Necromastery and can be quickly killed with Shadowraze.
* Shadow Fiend is a natural Black King Bar carrier, protecting him from any of Broodmother's abilities.
* Requiem of Souls combined with Eul's Scepter of Divinity can potentially kill Broodmother before she gets a Black King Bar.
Shadow Fiend
* The Reflection of Shadow Fiend cause Presence of the Dark Lord to affect Shadow Fiend, reducing his armor and making it easier for Terrorblade to kill him. Shadow Fiend also doesn't have lots of survivability or control abilities in order to escape.
* If Shadow Fiend chooses to go for a physical damage item build, he'll have a hard time against Terrorblade's high armor.
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.
Shadow Fiend
* 
Kraken Shell dispels both Shadowraze's damage amplification stacks and Requiem of Soul's damage reduction (provided Tidehunter has taken enough damage).
* 
Ravage cancels Requiem of Souls if Shadow Fiend isn't protected by Black King Bar.
Additional:
* Kraken Shell dispels the damage amplification stacks of Shadowraze as well as the damage reduction from Requiem of Souls (provided he has taken enough damage).
* Anchor Smash reduces Shadow Fiend's large attack damage, Kraken Shell makes Tidehunter the last target Shadow Fiend wants to attack.
* Ravage can easily cancel Requiem of Souls if Shadow Fiend isn't protected by Black King Bar.
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.
Shadow Fiend
* 
Shrapnel can be used to cancel Shadow Fiend's Blink Dagger from a huge range.
* 
Take Aim and 
Headshot allow Sniper to harass Shadow Fiend in lane without getting into the range of his Shadowrazes.
Additional:
* Shrapnel can be used to cancel Shadow Fiend's Blink Dagger from a huge range.
* Take Aim and Headshot allow Sniper to harass Shadow Fiend in lane without getting into the range of his Shadowraze.
* Assassinate when upgraded with Aghanim's Scepter can be used to cancel Shadow Fiend's Requiem of Souls.
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.
Shadow Fiend
* Decrepify prevents Shadow Fiend from attacking for its duration, potentially preventing him from getting a kill.
* Nether Ward can do heavy damage to Shadow Fiend if he tries to cast his Requiem of Souls and his Shadowraze.
Additional:
* 
Decrepify prevents Shadow Fiend from attacking for its duration, potentially preventing him from getting a kill.
* 
Nether Ward can do heavy damage to Shadow Fiend if he tries to cast his Requiem of Souls or spam Shadowraze.
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.
Shadow Fiend
* The blind from 
Laser prevents Shadow Fiend from attacking for its duration, potentially preventing him from getting a kill.
* Scythe of Vyse can be used to prevent Shadow Fiend from casting Requiem of Souls.
* A combination of Tinker's abilities and his items (like the 
Dagon 5 and Ethereal Blade combo) can kill Shadow Fiend quickly.
Additional:
* During the laning stage Laser will reduce Shadow Fiend's last hits, preventing him from getting Necromastery souls.
* Shadow Fiend has low health and is vulnerable to Tinker's high magic burst.
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.
Shadow Fiend
* Heroes with channeling spells because Shadow Fiend has nothing to cancel channeling outside of Requiem of Souls: Bane, Enigma, Pudge, Shadow Shaman, Dawnbreaker, Warlock, Crystal Maiden.
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 damage over time as Spiked Carapace can block and reflect only one instance of damage: Venomancer, Huskar, Ember Spirit, Dark Seer, Sand King, Doom, Dawnbreaker. However, this also means they are easily stunned.
Nyx Assassin
* Nyx Assassin can reflect Life Break with Spiked Carapace.
Shadow Fiend
* Shadow Fiend, a normal
Shadow Blade builder often relies on its invisibility to escape fights. Corrosive Haze reveals Shadow Fiend and also weakens his already low armor.
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.