* 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.

* Shukuchi cannot help Weaver escape from Arena of Blood, so with vision, Weaver is an easy kill.
* Time Lapse will also not save Weaver in a large amount of situations inside Arena of Blood, especially if he's pinned to the walls with Spear of Mars.
* The Swarm and Geminate Attack is not very useful against a hero that can tank 70% of his main damage source.

* Phantom Assassin's high physical damage is greatly reduced by Bulwark.
* God's Rebuke has true strike, ignoring the evasion from Blur.

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

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

* Heroes who cannot fight back during Arena of Blood in the early and mid game: Abaddon, Anti-Mage, Broodmother, Drow Ranger, Luna, Sniper, Troll Warlord, Weaver, Clinkz.

* Heroes who cannot fight back during Arena of Blood in the early and mid game: Abaddon, Anti-Mage, Broodmother, Drow Ranger, Luna, Sniper, Troll Warlord, Weaver, Clinkz.

* 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.

* Heroes that can negate Hoodwink's mobility: Kunkka, Disruptor, Mars.

* 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.

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

* Heroes who lack burst damage will have a hard time against Mars: Phantom Lancer, Nature's Prophet, Lich.

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

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

* Bulwark blocks the attack from Meepo and his clones.
* Spear of Mars & God's Rebuke prevents Meepo and his clones from initiation or escaping.

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

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

* Bulwark negates most of the physical damage from Terrorblade and his illusions.
* Mars' AoE abilities kill Terrorblade's illusions quickly.

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

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

* 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.

* Spectre cannot have a good game if she is pressured heavily in lane, which is something Mars can do.
* Spectre can use Haunt and Spectral Dagger inside and outside from Arena of Blood, but it doesn't really matter since Mars does best during the early and mid game.
* Should Spectre get to the late game, Mars can block a large amount of her damage and split the teamfights in his advantage.

* Bulwark blocks much of Slark's basic attack damage, even during Shadow Dance.
* Slark finds it very difficult to have a good early/mid game when pressured in the early game by Spear of Mars and God's Rebuke.
* Spear of Mars and God's Rebuke can hit Slark through Shadow Dance.
* Should Pounce be on cooldown, Slark is very vulnerable inside Arena of Blood.

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

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

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

* Mana Burn can instantly deplete Tidehunter's low mana pool, especially in the early game, potentially preventing Tidehunter from casting Ravage.
* Ravage's travel time allows Nyx Assassin to easily stun Tidehunter with Spiked Carapace.

* Monkey King's natural reliance on trees makes him an exceptionally prime target for Spear of Mars. Should Monkey King use Mischief to disguise himself, it will still hit him, stunning him in the process.
* God's Rebuke easily pushes Monkey King out of Wukong's Command.

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

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

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

* Heroes who can disable Mars but cannot do any damage to him, meaning he just tanks their abilities: Doom, Magnus.

* Heroes who lack burst damage will have a hard time against Mars: Phantom Lancer, Nature's Prophet, Lich.

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

* Heroes with the capability of removing or destroying trees greatly hinders the effectiveness of Treant Protector's abilities: Batrider, Nature's Prophet, Lina, Enigma, Mars

* Heroes who cannot fight back during Arena of Blood in the early and mid game: Abaddon, Anti-Mage, Broodmother, Drow Ranger, Luna, Sniper, Troll Warlord, Weaver, Clinkz.

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

* Heroes who lack burst damage will have a hard time against Mars: Phantom Lancer, Nature's Prophet, Lich.

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

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

* Heroes who cannot fight back during Arena of Blood in the early and mid game: Abaddon, Anti-Mage, Broodmother, Drow Ranger, Luna, Sniper, Troll Warlord, Weaver, Clinkz.

* 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.

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

* Heroes who cannot fight back during Arena of Blood in the early and mid game: Abaddon, Anti-Mage, Broodmother, Drow Ranger, Luna, Sniper, Troll Warlord, Weaver, Clinkz.

* Heroes who cannot fight back during Arena of Blood in the early and mid game: Abaddon, Anti-Mage, Broodmother, Drow Ranger, Luna, Sniper, Troll Warlord, Weaver, Clinkz.

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

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

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

* Arena Of Blood prevents Bloodseeker from attacking a Ruptured target.
* Bulwark helps Mars survive Rupture ganks simply by turning towards Bloodseeker without moving.
* Spear of Mars and God's Rebuke can push Bloodseeker from Ruptured targets.

* 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.

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

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

* Heroes who can disable Mars but cannot do any damage to him, meaning he just tanks their abilities: Doom, Magnus.

* Nyx Assassin might not kill Abaddon with his nuke, but a support Abaddon will struggle to protect an ally from him.

* Heroes who cannot fight back during Arena of Blood in the early and mid game: Abaddon, Anti-Mage, Broodmother, Drow Ranger, Luna, Sniper, Troll Warlord, Weaver, Clinkz.

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

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

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

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

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

* Heroes who cannot fight back during Arena of Blood in the early and mid game: Abaddon, Anti-Mage, Broodmother, Drow Ranger, Luna, Sniper, Troll Warlord, Weaver, Clinkz.

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

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

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

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

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

* 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 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 Devourer's high mana pool, high intelligence, and low health makes him a prime target for Mana Burn.
* If timed correctly, Spiked Carapace will return the full damage from Sanity's Eclipse back to Outworld Devourer. Even a reflected Arcane Orb can deal significant damage and make him vulnerable to a follow-up from Nyx Assassin.
* Spiked Carapace is also the perfect tool against Astral Imprisonment: if used on Nyx, he can reflect the damage back as he comes out of the prison by casting the ability while imprisoned.

* Juggernaut deals mostly physical damage, which is easily mitigated with Bulwark.
* Juggernaut's Omnislash switches to opposite directions which each slash, so Mars can mitigate most of its damage since he only takes full damage from one direction: his back.

* Heroes that are hard to gank: Dragon Knight, Mars, Centaur Warrunner.

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

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

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