* While Terrorblade can kill Crystal Maiden due to her low durability with Reflection and Metamorphosis, Crystal Maiden can do the same to him if he is not careful.
* Crystal Nova and Freezing Field can destroy Terrorblade's Illusions from Conjure Image and Manta Style while it can also kill Terrorblade from early to mid game if he has no Black King Bar.
* Terrorblade has no disable in his ability set at all and has no solutions to cancel it Freezing Field. In addition, he doesn't like purchasing disabling items like Scythe of Vyse or Abyssal Blade, which are the only solutions to deal with Crystal Maiden's Freezing Field outside of Black King Bar.
* Since Crystal Maiden often buys Black King Bar and Glimmer Cape, or it's alternative item Shadow Blade, as well as it's upgrade Silver Edge, Terrorblade will rarely have a chance to save himself against Crystal Maiden's damage output with Sunder.
Additional:
* While Terrorblade can easily kill Crystal Maiden due to her low durability and movement speed with Reflection and Metamorphosis, Crystal Maiden can do the same to him if he is not careful.
* Crystal Nova and Freezing Field can destroy Terrorblade's illusions from Conjure Image and Manta Style while it can also kill Terrorblade from early to mid game if he has no Black King Bar.
* Terrorblade has no disable in his ability set at all and has no solutions to cancel it Freezing Field. In addition, he doesn't like purchasing disabling items like Scythe of Vyse or Abyssal Blade, which are the only solutions to deal with Crystal Maiden's Freezing Field outside of Black King Bar.
* Since Crystal Maiden often buys Black King Bar and Glimmer Cape, or it's alternative items Shadow Blade, as well as it's upgrade Silver Edge or Linken's Sphere, Terrorblade will rarely have a chance to save himself against Crystal Maiden's damage output with Sunder.

* Nyx Assassin deals large amounts of pure damage with Vendetta and magical damage with Impale and Mana Burn, 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.
* Mana Burn might drain too much mana for Terrorblade to be able to use Sunder if he isn't careful in the early to mid game.

* Heroes that mainly use magic damage and carry Black King Bar can be very problematic for Muerta such as Crystal Maiden or Clockwerk

* As a counter to most casters,Nyx will shut down Muerta with only a few items.
* Nyx's Mana Burn can make short work of Muerta's high intelligence pool.
* Spiked Carapace and Vendetta can help Nyx escape or imitate when needed.

* Heroes like Enchantress and Chen, or heroes that make use of Helm of the Dominator are weak to Crystal Maiden, as Frostbite can do wonders against Enchant, Holy Persuasion, or dominated creeps. Careful though, as an army of carefully controlled creeps (Enchantress and Chen) can hold many stuns that will cancel Freezing Field.

Additional:
* Frostbite does 1000 magical damage to Enchantress's creeps and roots them for 10 seconds, which hinders her ability to gank.

* 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.
* 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.

* Heroes with mobility spells like Queen of Pain, Anti-Mage, Phantom Assassin, Riki, Puck, and Spirit Breaker that are cancelled by Frostbite can suffer greatly from the presence of Crystal Maiden. It is absolutely critical, however, to have followup from teammates, as all of the above heroes can make quick work of the squishy Crystal Maiden after they are released from her grip.

* 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.

* Heroes with channeling abilities: Enigma, Witch Doctor, Crystal Maiden.

* 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.
* However, Mana Burn's Mana Burn can be more or less mitigated with Chakra Magic.

* Frostbite will reveal invisible heroes for its duration, making it a good tool against any such hero (Riki, Bounty Hunter, Weaver, or Clinkz for example), or as a soft counter to Shadow Blade, if it is used first. This can be an amazing tool to ensure that Dust of Appearance is used on the unit in question, and not wasted in not catching anything.

* 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.

* Frostbite roots and disarms Chen's creeps for 10 seconds.
* Crystal Maiden has a lot of AOE damage between Crystal Nova and Freezing Field to clear Chen's creeps out side and during team fights.

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

* Level 4 Mana Burn burns of Medusa's mana every 5 seconds if Medusa only increases her mana pool with intelligence. Additionally, 70% 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.
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.

* 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. 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.

* 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 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 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.

* Spiked Carapace stops Snapfire's Mortimer Kisses.

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

* Mana Burn removes much-needed mana for Ball Lightning.
* Spiked Carapace triggers on Static Remnant for an easy stun.
Additional:
* 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.

* 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.

* Due to her slow movement speed,heroes with crowd control and slows can shut down Dawnbreaker. ( Lion, Crystal Maiden ,Venomancer etc.)

* 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.

* 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 mana pool and high intelligence 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 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.

* Frostbite kills boars instantly on the laning stage leading to either experience lead or disabling Beastmaster from using Boar
* Crystal Nova nukes and slows down the attack and movement speed of Beastmaster's summons.
* Freezing Field grants improved self armor, nukes and slows down Beastmaster and his summons.

* 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.

* Though Slark's large damage output is most certainly a concern for the squishy Crystal Maiden, she does perform fairly well against him when coupled with aid from her team.
* Slark has no innate way to cancel Freezing Field, but the common purchase of Skull Basher does make Slark a substantially greater threat to Crystal Maiden as the game progresses.
* Freezing Field can still hit Slark while he is under the effect of Shadow Dance, and for the early and mid game, the damage output of Crystal Maiden's ultimate outscales Slark's passive regeneration, making a quick use of Freezing Field as soon as Slark uses Shadow Dance a great way to combat him.
* Crystal Maiden's Frostbite and Crystal Nova are helpful in disabling and slowing the slippery Slark so he can be killed by her teammates.

* Though certainly not a "hard counter", Crystal Maiden's skillset (magical damage nukes) does pose a substantial threat to Phantom Assassin through the mid game, especially if followed up with engagement by her team.
* A quick use of Freezing Field directly after Phantom Strike can leave Phantom Assassin trapped inside the area of effect, capitalizing on Phantom Assassin's relatively low HP pool when she is not protected by Blur, and besides Skull Basher, Phantom Assassin hates buying disabling items like Scythe of Vyse or Eul's Scepter of Divinity.
* If Phantom Assassin chooses not to buy a Black King Bar relatively early, the attack slow from Freezing Field can greatly hinder the proc chance of Coup de Grace in a teamfight.
* However, Phantom Assassin's massive damage, and her tendency to build both Black King Bar and Skull Basher makes her a formidable foe the later the game goes, and fighting her without a team is almost never a good choice.

* 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 gains an item advantage: Lina, Necrophos, Nyx Assassin, Gyrocopter. Should be noted these heroes are usually quite squishy and don't scale well with health. So to some respect, they are on a time crunch.

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

* 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.

* Large area-of-effect with delay or require channeling: Enigma, Crystal Maiden, Invoker, Shadow Fiend, Pugna, Keeper of the Light, Dawnbreaker.

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

* Heroes with mobility spells like Queen of Pain, Anti-Mage, Phantom Assassin, Riki, Puck, and Spirit Breaker that are cancelled by Frostbite can suffer greatly from the presence of Crystal Maiden. It is absolutely critical, however, to have followup from teammates, as all of the above heroes can make quick work of the squishy Crystal Maiden after they are released from her grip.

* Heroes with mobility spells like Queen of Pain, Anti-Mage, Phantom Assassin, Riki, Puck, and Spirit Breaker that are cancelled by Frostbite can suffer greatly from the presence of Crystal Maiden. It is absolutely critical, however, to have followup from teammates, as all of the above heroes can make quick work of the squishy Crystal Maiden after they are released from her grip.

* 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 Mana Burn that much more deadly against Puck.
* An ill-timed Phase Shift can turn into an easy setup for Impale.

* 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.

* Heroes who can slow and kite Axe will severely inhibit his presence in fights: Bristleback, Crystal Maiden, Batrider, Arc Warden, Winter Wyvern, Clockwerk

* 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.
* 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.

* 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.

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

* As with other heroes mentioned in this section, Templar Assassin is not a hero that is fully "countered" by Crystal Maiden (the way she is against Viper and Jakiro), however, the proper combination and execution Crystal Maiden's spells, stacked with her team, can most certainly spell the end for Templar Assassin. Though as the later the game goes, and fighting her without team is not the best choice.
* Frostbite can quickly eat away Refraction charges, leaving Templar Assassin vulnerable for the rest of her team to kill.
* Freezing Field will still apply damage to Templar Assassin when she is under the effect of Meld, making it an even less viable form of escape until a Blink Dagger is purchased.
* Blink Dagger is also cancelled by all of Crystal Maiden's spells, and the fairly short cooldowns on Frostbite and Crystal Nova make her a great asset to a chase against Templar Assassin.
* This is not to say that Templar Assassin has any difficulty killing off the low armor, low HP pool Crystal Maiden, so fighting her alone is never advised.

* 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.

* Frostbite can disarm and root Troll Warlord if he doesn't have a Black King Bar or a Manta Style to dispel it.
* Crystal Nova and Freezing Field both significantly slow Troll Warlord, making him much more vulnerable to ganks or stuns.
* The magical damage from Freezing Field does a large amount of AoE damage, and Troll Warlord is not capable of cancelling Crystal Maiden's channel.

* 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.

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

* 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.

* 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.

* 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.
* 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.

* Heroes the make heavy use of illusions, like Chaos Knight, Phantom Lancer, Terrorblade, or Spectre can suffer from Crystal Maiden, as Freezing Field can quickly kill off the entire horde if not stopped.

* Heroes with powerful rooting abilities will disable most of Pangolier's skills, a bonus point if it pierces spell immunity since it will also be able to stop Pangolier during his Rolling Thunder: Treant Protector, Meepo, Crystal Maiden, Dark Willow, Underlord, Naga Siren

* 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.

* Mana Burn drains Pudge's little mana which may render Meat Hook and Dismember unusable.
* 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.

* 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.

* 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.

* Heroes the make heavy use of illusions, like Chaos Knight, Phantom Lancer, Terrorblade, or Spectre can suffer from Crystal Maiden, as Freezing Field can quickly kill off the entire horde if not stopped.

* Frostbite will reveal invisible heroes for its duration, making it a good tool against any such hero (Riki, Bounty Hunter, Weaver, or Clinkz for example), or as a soft counter to Shadow Blade, if it is used first. This can be an amazing tool to ensure that Dust of Appearance is used on the unit in question, and not wasted in not catching anything.

* 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 Mana Burn will deal increasing damage for each point of intelligence Silencer has stolen, turning Silencer's intelligence steal against him.