* Phantom Strike's extra attack speed will cause Phantom Assassin to trigger Counter Helix more often, which can be fatal for Phantom Assassin. Jumping on Axe with Phantom Strike is not a good idea for Phantom Assassin at all as it makes her a seriously easy target for a counter-initiation with Berserker's Call and Blade Mail.
* Most of Axe's abilities pierce Black King Bar, allowing him to lock down Phantom Assassin at any time.
* Berserker's Call greatly reduces Phantom Assassin's ability to crit hard against Axe and may cause her to kill herself when used with Blade Mail. Berserker's Call can also affect Phantom Assassin even if she has Black King Bar active as Berserker's Call can fully pierce spell immunity, making Berserker's Call one of the best abilities in the game against heroes like Phantom Assassin who wants to kill opponents quickly without being interrupted.
* Culling Blade can often kill Phantom Assassin before she can do anything due to her low health and strength gain. And every time Culling Blade successfully kills Phantom Assassin or any of her teammates, Axe gains permanent armor from it, which in combination with armor items that Axe often purchases like Blade Mail, Crimson Guard, Assault Cuirass and Shiva's Guard can make Phantom Assassin's attacks only tickle Axe.
* Aghanim's Shard upgraded Counter Helix can weaken Phantom Assassin's damage output, and if her attack damage is weak, Coup De Grace will also suffer from attack damage reduction as well.
Additional:
* Phantom Strike's extra attack speed will cause Phantom Assassin to trigger Counter Helix more often, which can be fatal for Phantom Assassin in the early game. Jumping on Axe with Phantom Strike is not a good idea for Phantom Assassin at all as it makes her a seriously easy target for a counter-initiation with Berserker's Call and Blade Mail.
* Most of Axe's abilities pierce Black King Bar, allowing him to lock down Phantom Assassin at any time.
* Berserker's Call greatly reduces Phantom Assassin's ability to crit hard against Axe, and may cause her to kill herself when used with Blade Mail. Berserker's Call can also affect Phantom Assassin even if she has Black King Bar active as Berserker's Call can fully pierce spell immunity, making Berserker's Call one of the best abilities in the game against heroes like Phantom Assassin who wants to kill opponents quickly without being interrupted.
* Culling Blade can often kill Phantom Assassin before she can do anything due to her low health and strength gain. And every time Culling Blade successfully kills Phantom Assassin or any of her teammates, Axe gains permanent armor from it, which in combination with armour items that Axe often purchases like Blade Mail, Crimson Guard, Assault Cuirass and Shiva's Guard can make Phantom Assassin's attacks only tickle Axe.

* Axe will destroy her illusions by proccing Counter Helix more often due to him being hit by more attacks.

* Morphling's naturally high armor thanks to his high agility makes it hard for Phantom Assassin to take him down with Coup de Grace.

* Waveform clear Mirror Image illusions from Naga Siren. And though Ensnare can prevent Morphling from using Waveform to escape, he can easily dispel it with Manta Style, a common item on Morphling.
* Morph allows Morphling to copy Naga Siren's abilities and combine them with Manta Style, a commong item for Morphling, to destroy Naga Siren's illusions. Aghanim's Scepter upgraded Morph also allows Morphling to create a strong illusion of Naga Siren that can do the same and which can also allow Morphling to close the gap on Naga Siren.

* Reactive Armor helps Timbersaw sustain harassment from Stifling Dagger.
* Phantom Assassin has a moderate health pool and usually appears in the front line of battle, making her vulnerable to Timbersaw's pure burst damage output.
* Timbersaw can easily escape from Phantom Assassin thanks to his Timber Chain.
Additional:
* Reactive Armor helps Timbersaw sustain harassment from Stifling Dagger, as well as ganking attempts.
* Phantom Assassin is a hero with moderate HP pool, and usually appears in the front line of battle. Because Blur does nothing against spells, she is vulnerable to Timbersaw's skills.
* Timbersaw can easily escape from Phantom Assassin thanks to his Timber Chain.

* Timbersaw's innate durability provided by Reactive Armor is very hard to deal with as Naga Siren as she mostly relies on sustained damage rather than burst damage unless if she is played as Nuker.
* Timbersaw's high pure damage and low-cooldown area-of-effect nukes which are Whirling Death, Timber Chain, Chakram and Flamethrower from Aghanim's Shard can also destroy Naga Siren's illusions very fast.
* Timbersaw is a common Lotus Orb wielder which allows him to reflect Ensnare back at Naga SIren.

* Phantom Assassin does not deal with early aggression very easily (especially when magical damage). A competent Batrider can make life very difficult with Sticky Napalm followed by any other spell.

* Many stacks of Sticky Napalm, combined with Flamebreak and Firefly, allows Batrider to destroy illusions from Mirror Image.
* If Batrider can manage to destroy all illusions from Naga Siren, he will be able to use Flaming Lasso on the real one, and will be able to drag her toward his team, potentially preventing Naga Siren from escaping with Song of the Siren.
Additional:
* Many stacks of Sticky Napalm, combined with Flamebreak and Firefly, allows Batrider to destroy illusions from Mirror Image.
* If Batrider can manage to destroy all illusions from Naga Siren, he will be able to use Flaming Lasso on the real one, and will be able to drag her toward his team, potentially preventing Naga Siren from escaping with Song of the Siren.

* Any heroes with low mana pools will die quickly or even instantly to Sanity's Eclipse: Doom, Phantom Assassin, Troll Warlord.

* Arcane Orb allows Outworld Destroyer's attacks to deal pure damage that can bypass Naga Siren's armor, and which can clear her illusions in no time.
* Astral Imprisonment can be used to harass Naga Siren by reducing her maximum mana and to prevent Naga Siren from escaping with Song of the Siren. Outworld Destroyer can also use Astral Imprisonment to protect himself from Naga Siren.
* Sanity's Eclipse will most likely instantly kill Naga Siren along with her illusions. Even if Naga Siren survives Sanity's Eclipse, it's mana allergy debuff will discourage Naga Siren from using her abilities as the mana allergy will heal Outworld Destroyer if she uses them for it's duration.

* Heroes capable of perofrming interceptions who can anticipate and counter-initiate after Phantom Assassin blinks on them with Phantom Strike will often kill her than the other way around: Axe, Bane, Dawnbreaker, Centaur Warrunner, Luna, Medusa, Omniknight, Pudge, Razor, Terrorblade, Underlord.

* Dawnbreaker can easily clear waves of Naga Siren's illusions from Mirror Image with Starbreaker, Celestial Hammer and Solar Guardian.
* Aghanim's Shard upgraded Starbreaker will allow Dawnbreaker to dispel Ensnare and freely attack Naga Siren during Song of the Siren when combined with Black King Bar, a common item on Dawnbreaker.
* Solar Guardian allows Dawnbreaker to counter any attempts of Naga Siren and rejoin her team with Solar Guardian when they require it. Aghanim's Scepter upgraded Solar Guardian can also give Dawnbreaker's allies evasion while Dawnbreaker is airborne for it's duration, as Naga Siren mainly relies on direct attacks in order to deal damage.
Additional:
* Dawnbreaker can easily clear waves of Naga Siren's illusions from Mirror Image with Starbreaker, Celestial Hammer and Solar Guardian.
* Aghanim's Shard upgraded Starbreaker will allow Dawnbreaker to dispel Ensnare and freely attack Naga Siren during Song of the Siren when combined with Black King Bar, a common item on Dawnbreaker.
* Solar Guardian allows Dawnbreaker to counter any pushing attempts of Naga Siren and rejoin her team with Solar Guardian when they require it. Aghanim's Scepter upgraded Solar Guardian can also give Dawnbreaker's allies evasion while Dawnbreaker is airborne for it's duration, as Naga Siren mainly relies on direct attacks in order to deal damage. Solar Guardian can also be used after Naga Siren uses Song of the Siren near her allies to either escape from or counter-initiate against them.

* Heroes with heavy early and mid-game magical damage are also problematic for Phantom Assassin due to being able to easily kill her before she can gain an item advantage over them: Lina, Necrophos, Nyx Assassin, Gyrocopter, Jakiro, Death Prophet.

* Flak Cannon and Call Down can easily clear Naga Siren's illusions.

* Despite her high mobility, Hex or Earth Spike can lock Phantom Assassin down, make her vulnerable and mitigate her damage output.
* Lion relies entirely on his abilities to be effective, rendering Phatnom Assassin's high evasion through ineffective against him. And Phantom Assassin's low health pool makes her vulnerable to Lion's magical burst without Black King Bar.

* Lion may upgrade Mana Drain, Hex and Finger of Death through Talent Tree and Aghanim's itens to make them affect secondary targets or turn them into AoE abilities. This can make things difficult for heroes like Phantom Lancer, Naga Siren and Terrorblade, who rely on illusion armies.

Additional:
* Both Hex and Mana Drain destroy Naga Siren's illusions in an instant, making it hard for her to teamfight or push against a team with Lion. If Lion chooses the AoE effect talent for Hex or the shard for multi-target Mana Drain, it can negate her pushing potential entirely.
* Earth Spike is an AoE disable with good damage. If used well, it can help distinguish the true Naga Siren by the damage they take (illusions take more damage).

* Hoof Stomp and Double Edge can often burst down Phantom Assassin from early to mid game.
* Retaliate makes it very unlikely for Phantom Assassin to win the lane against Warrunner. Double Edge can also be used to wear her down, as she has a much smaller health pool than that of Centaur Warrunner until purchasing a Ring of Health. Stifling Dagger will also trigger Retaliate and Blur cannot evade Retaliate.
* Centaur Warrunner's tankiness in combination with armour items that Axe often purchases like Blade Mail, Crimson Guard, Assault Cuirass and Shiva's Guard can make Phantom Assassin's attacks only tickle Centaur Warrunner.
* Centaur Warrunner just has to be careful about Fan of Knives from Aghanim's Shard and Coup De Grace, as Fan of Knives can disable Retaliate even if Centaur Warrunner is spell immune.
Additional:
* Hoof Stomp and Double Edge can often burst down Phantom Assassin from early to mid game.
* Retaliate makes it very unlikely for Phantom Assassin to win the lane against Warrunner. Double Edge can also be used to wear her down, as she has a much smaller health pool than that of Centaur Warrunner until purchasing a Ring of Health. Stifling Dagger will also trigger Retaliate and Blur cannot evade Retaliate.
* Centaur Warrunner's tankiness in combination with armour items that Centaur Warrunner often purchases like Blade Mail, Crimson Guard, Assault Cuirass and Shiva's Guard can make Phantom Assassin's attacks only tickle Centaur Warrunner.
* Centaur Warrunner just has to be careful about Fan of Knives from Aghanim's Shard and Coup De Grace, as Fan of Knives can disable Retaliate even if Centaur Warrunner is spell immune.

* Heroes who are reliant on illusions: Chaos Knight, Phantom Lancer, Naga Siren.

Additional:
* Centaur's Retaliate will harm all attacking enemies, which will allow Centaur Warrunner to see which is the real Naga Siren.
* A well timed Hoof Stomp followed by Double Edge will clear all Naga's illusions and prevent Naga Siren from escaping with Song of the Siren.

* Phantom Assassin's Blur is useless against Windranger as she commonly buys items that require Javelin like Maelstrom, Monkey King Bar or Bloodthorn, and other than Stifling Dagger, Phantom Assassin has nothing else that can bypass Windrun.
* Additionally, Phantom Assassin doesn't like building Monkey King Bar because her crits are reliant on attack damage.
* Focus Fire can still deal considerable damage despite Blur's evasion due to the increased attack speed.
Additional:
* Phantom Assassin's Blur is useless against Windranger as she commonly buys items that require Javelin like Maelstrom, Monkey King Bar or Bloodthorn, and other than Stifling Dagger, Phantom Assassin has nothing else that can bypass Windrun.
* Additionally, Phantom Assassin doesn't like building Monkey King Bar because her crits are reliant on attack damage.
* Focus Fire can still deal considerable damage despite Blur's evasion due to the increased attack speed.

* As long as Windranger is able to identify the real hero among the illusions, heroes relying on them can be easily tagged with Focus Fire: Chaos Knight, Terrorblade, Phantom Lancer, Naga Siren.

* Phantom Assassin relies on her Blur to stay alive, but is very vulnerable to Sand King's heavy magic damage.
* With Burrowstrike, Sand King can often catch Phantom Assassin before she can use her Black King Bar.
* Sand King can dodge Stifling Dagger with Sandstorm.
* Phantom Assassin has a hard time killing Sand King because of his high mobility.

* Since Naga Siren is a hero who barely goes for Black King Bar, she is vulnerable to nukers with strong magical damage and big area-of-effect spells in every game more than any other carry heroes: Sand King, Jakiro, Leshrac, Lina, Earthshaker, Zeus.

* Firestorm can deal serious damage to Phantom Assassin during laning.
* Pit of Malice prevents Phantom Assassin from either escaping or engaging with Phantom Strike.
* Phantom Assassin's damage output is entirely physical, therefore Atrophy Aura is very hazardous for her in most of the stages, particularly since it also affects Coup De Grace, hindering Phantom Assassin's main source of damage.
* Without proper items and any area-of-effect ability/item, Phantom Assassin cannot stop Underlord and his team to escape with Fiend's Gate, and she has nothing to intercept Underlord and his team when they use Fiend's Gate to teleport on any area of the map outside of Fan of Knives from Aghanim's Shard.
Additional:
* Firestorm can be used to deal serious damage to Phantom Assassin during laning that ignores evasion from Blur.
* Pit of Malice prevents Phantom Assassin from either escaping or engaging with Phantom Strike.
* Phantom Assassin's damage output is entirely physical, therefore Atrophy Aura is very hazardous for her in most of the stages, particularly since it also affects Coup De Grace, hindering Phantom Assassin's main source of damage.
* Without proper items and any area-of-effect ability/item, Phantom Assassin cannot stop Underlord and his team to escape with Fiend's Gate, nor she can intercept them if Underlord chooses to teleport on any area of the map.

* Atrophy Aura makes it hard or Naga Siren to farm on lane and damage Underlord with Rip Tide in teamfights. And her only way to counter this is by playing Nuker role.
* Firestorm is very useful for clearing Naga Siren's illusions from Mirror Image and Manta Style.
* However, Naga Siren can catch Underlord and his team unprepared with Song of the Siren if he chooses to use Fiend's Gate to get to a designated point of the map. Naga Siren can also prevent escaping with Fiend's Gate with Ensnare and Reel In from Aghanim's Scepter.
Additional:
* Atrophy Aura makes it hard or Naga Siren to farm on lane and damage Underlord with Rip Tide in teamfights. And her only way to counter this is by playing Nuker role.
* Firestorm is very useful for clearing Naga Siren's illusions from Mirror Image and Manta Style.
* However, Naga Siren can catch Underlord and his team unprepared with Song of the Siren if he chooses to use Fiend's Gate to get to a designated point of the map. Naga Siren can also prevent escaping with Fiend's Gate with Ensnare and Reel In from Aghanim's Scepter.

* Heroes with high mobility can be prevented from using it to their advantage with Earthbind, even if they pack a dangerous arsenal: Earth Spirit, Ember Spirit, Storm Spirit, Nature's Prophet, Phantom Assassin, Riki, Anti-Mage, Weaver.
* See items and abilities disabled by roots

* Naga Siren's Song of the Siren may be useful but Poof will destroy all of her illusions.

* With Normal Punch from Aghanim's Scepter, Dark Seer can gain an advantage against heroes who rely on evasion as Normal Punch has true strike: Phantom Assassin, Windranger, Hoodwink.

* Heroes that rely on illusions typically spawn very strong illusions inside Dark Seer Wall of Replica that he can use against them or their team: Phantom Lancer, Chaos Knight, Naga Siren, Terrorblade.

* Heroes that rely on physical damage are ineffective against Dragon Knight due to his high armor: Phantom Assassin,Bloodseeker, Lifestealer, Troll Warlord, Sven

* Heroes whose attacks can affect multiple enemies at once will clear Naga Siren's illusions. Such heroes include Sven, Magnus, Dragon Knight, Luna, Medusa, Templar Assassin, Gyrocopter, Muerta.

* Heroes with disables that ignore spell immunity will render Phantom Assassin completely useless in teamfights throughout the game: Axe, Enigma, Vengeful Spirit, Doom, Bane, Beastmaster, Pudge, Medusa, Warlock.

* Heroes with AoE nukes will clear her illusions in no time, especially if they are percentage-damage-based, like Underlord's Firestorm, Elder Titan's Earth Splitter, Enigma's Midnight Pulse, Zeus's Arc Lightning, Jakiro's Liquid Frost from Aghanim's Shard etc.

* Heroes with gap-closing abilities who attempt to use them for escaping Bloodseeker will suffer serious damage from Rupture: Phantom Assassin, Anti-Mage, Faceless Void, Riki, Slark, Spirit Breaker.

* Heroes with long-lasting, undispellable debuffs will pinpoint the true Naga Siren: Spirit Breaker, Bloodseeker, Witch Doctor.

* Heroes who cannot prevent Sven from killing towers will often struggle from a small map very early, such as Phantom Assassin, Storm Spirit and Phantom Lancer.

* Heroes whose attacks can affect multiple enemies at once will clear Naga Siren's illusions. Such heroes include Sven, Magnus, Dragon Knight, Luna, Medusa, Templar Assassin, Gyrocopter, Muerta.

* Phantom Assassin's single target abilities make her very helpless against swarms of Spiderlings without Battle Fury.
* Because Phantom Assassin is always reliant on critical strikes, Broodmother will usually have enough time to use Spin Web to save herself.
* Silken Bola can cripple Phantom Assassin greatly due to her being 100% reliant on physical attacks.
* Aghanim's Scepter gives Broodmother access to Spinner's Snare, which allows her to create invisible lines on her webs from Spin Web that will root Phantom Assassin, deal damage over time to Phantom Assassin and reveal Phantom Assassin if she unwittingly steps on them, disrupting her attempts to initiate or escape with with Phantom Strike while also alerting Broodmother on her attempts to ambush her and her allies.
Additional:
* Phantom Assassin's single target abilities make her very helpless against swarms of Spiderlings without Battle Fury.
* Because Phantom Assassin is always reliant on critical strikes, Broodmother will usually have enough time to use Spin Web to save herself.
* Silken Bola can cripple Phantom Assassin greatly due to her being 100% reliant on physical attacks.
* Aghanim's Scepter gives Broodmother access to Spinner's Snare, which allows her to create invisible lines on her webs from Spin Web that will root Phantom Assassin, deal damage over time to Phantom Assassin and reveal Phantom Assassin if she unwittingly steps on them, disrupting her attempts to initiate or escape with with Phantom Strike while also alerting Broodmother on her attempts to ambush her and her allies.

* Heroes with disables that ignore spell immunity will render Phantom Assassin completely useless in teamfights throughout the game: Axe, Enigma, Vengeful Spirit, Doom, Bane, Beastmaster, Pudge, Medusa, Warlock.

* Medusa's Split Shot and Mystic Snake combined with Mjollnir, a common item for Medusa, will whittle down all of Naga Siren's illusions, including Naga Siren herself.
* Medusa's Stone Gaze can disable Naga Siren even for the duration of Song of the Siren and even if Naga Siren is spell immune, discouraging Naga Siren from even trying to use Song of the Siren to save herself or counter-initiate against Medusa.
Additional:
* Medusa's Split Shot and Mystic Snake combined with Mjollnir, a common item for Medusa, will whittle down all of Naga Siren's illusions, including Naga Siren herself.
* Medusa's Stone Gaze can disable Naga Siren even for the duration of Song of the Siren and even if Naga Siren is spell immune, discouraging Naga Siren from even trying to use Song of the Siren to save herself or counter-initiate against Medusa.

* Zeus's abilities deal high amounts of burst magical damage, which ignores Naga Siren's high armor.
* Arc Lightning is a good way to destroy Naga Siren's illusions due to it's capabilities to bounce between enemies.
* Static Field from Aghanim's Shard can automatically hit everything in a big radius, taking a huge chunk of health out of Naga Siren's illusions, regardless of how much health they have.

* Mirror Image's illusions increase Echo Slam's damage.
Additional:
* Earthshaker's strong AoE abilities can clear Naga Siren's illusions, or at least make it easier to distinguish the real one by the damage they take.
* Echo Slam deals more damage against more enemies, which can be devestating against Naga Siren and her illusions.

* Jakiro's reliance on his abilities can cause struggles for heroes who rely on evasion or blinds to get upper hand: Phantom Assassin, Windranger, Riki, Troll Warlord, Keeper of the Light.

* Jakiro's damage over time abilities can clear Naga Siren's illusions and can hurt real Naga Siren even for the duration of Song of the Siren.
* Naga Siren is not a hero that likes to go for Black King Bar, and that makes her very vulnerable to Jakiro's damage over time in every phase of the game.
Additional:
* Jakiro's damage over time abilities can clear Naga Siren's illusions and can hurt real Naga Siren even for the duration of Song of the Siren.
* Since Naga Siren is a hero who barely goes for Black King Bar, this can make her very vulnerable to Jakiro's damage over time in every phase of the game.

* All of Leshrac's abilities, especially Pulse Nova, can easily deal with Naga Siren's illusions.
* Aghanim's Scepter gives Leshrac access to Nihilism ability, that allows him to turn himself along with Naga Siren and her illusions to turn ethereal. And to make things worse, Nihilism can slow Naga Siren and her illusions, make them more vulnerable to magical damage and unable to fight back while Leshrac moves faster and does not take increased magical damage for it's duration.

* Puck relies mainly on magical burst damage, which Phantom Assassin is most vulnerable against.
* Phase Shift and Illusory Orb disjoint Stifling Dagger, also allowing to kite Phantom Assassin.
* Dream Coil will stun Phantom Assassin if she uses Phantom Strike to blink away.

* Whirling Axes (Melee) makes it hard for Phantom Assassin to land a Coup De Grace.
* Troll Warlord often buys Silver Edge and Monkey King Bar, the items that greatly help against Phantom Assassin's Blur ability.
* Battle Trance completely negates Phantom Assassin's large damage output, preventing Troll Warlord from dying easily. The lifesteal also allows Troll Warlord to restore much of his health.
Additional:
* Troll Warlord can build a Silver Edge or a Monkey King Bar to completely ignore Blur.
* Whirling Axes (Melee) provides a 60% miss chance, making a Coup de Grace critical strike very hard to land.
* Battle Trance negates Coup de Grace, preventing Troll Warlord from dying to her critical hits.

* Mortimer Kisses can make quick work of Naga Siren's illusions.
* Scatterblast and Firesnap Cookie's AoE damage are also decent ways to deal with Naga's illusions.

* Overgrowth prevents Phantom Assassin from using Blink Strike even through her spell immunity.
* Living Armor reduces Phantom Assassin's physical damage whenever she attempts to gank an allied hero.

* Static Link can lower the damage output from Coup de Grace procs, hindering Phantom Assassin's main source of damage. And Phantom Assassin is not a common Linken's Sphere wielder to counter this problem.
* Eye of the Storm strikes cannot be evaded by Blur.
* Both Static Link and Eye of the Storm pierces spell immunity, as Phantom Assassin is often reliant on Black King Bar.
Additional:
* Static Link can lower the damage output from Coup de Grace procs, hindering Phantom Assassin's main source of damage.
* Eye of the Storm strikes cannot be evaded by Blur.
* Both Static Link and Eye of the Storm pierces spell immunity, as Phantom Assassin is often reliant on Black King Bar.

* Dispersion makes it hard for Phantom Assassin to burst down Spectre while also reflecting back Phantom Assassin's high burst damage against herself.
* Black King Bar is useless for Phantom Assassin against Spectre as all of her skills pierce spell immunity.
* Spectre only needs to be careful against Fan Of Knives from Aghanim's Shard, as it can disable Desolate and Dispersion, though this issue can be solved by buying Blade Mail, which is a common item on Spectre.
Additional:
* Dispersion makes it hard for Phantom Assassin to burst down Spectre while also reflecting back Phantom Assassin's high burst damage against herself.
* Black King Bar is useless against Spectre as all of her skills pierce spell immunity.

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

* Sharpshooter disables both Blur and Coup De Grace, especially with the level 25 talent.
* Because Phantom Assassin is often reliant on critical strikes, Hoodwink can have enough time to simply move near a tree and escape with Scurry.
Additional:
* Sharpshooter disables both Blur and Coup De Grace, weakening her damage and survivability.
* Because Phantom Assassin is often reliant on critical strikes, Hoodwink can have enough time to simply move near a tree and escape with Scurry.

* Laguna Blade is one of the best tools to kill Phantom Assassin before she can do anything in early-to-mid game due to its high magical (pure with Laguna Blade damage is Pure and pierces Spell Immunity talent) burst damage.
* Blur offers no protection against Lina's abilities. Likewise, Lina can counter Blur's evasion by buying either Silver Edge or Monkey King Bar.
* Lina just has to be careful about Fan of Knives from Aghanim's Shard and Coup De Grace, as Fan of Knives can deal pure damage to Lina and disable Fiery Soul awhile Coup De Grace can deal serious damage to her even if she is spell immune, which may force Lina to buy Ethereal Blade to deal with Phantom Assassin.
Additional:
* Laguna Blade is one of the best tools to kill Phantom Assassin before she can do anything in early-to-mid game due to its high magical (pure with Laguna Blade damage is Pure and pierces Spell Immunity talent) burst damage.
* Blur offers no protection against Lina's abilities. Likewise, Lina can counter Blur's evasion by buying either Silver Edge or Monkey King Bar.
* Lina just has to be careful about Fan of Knives from Aghanim's Shard and Coup De Grace, as Fan of Knives can deal pure damage to Lina and disable Fiery Soul awhile Coup De Grace can deal serious damage to her even if she is spell immune, which may force Lina to buy Ethereal Blade to deal with Phantom Assassin.

* Heroes with summons and illusions can find themselves easily bested by Lina, like Broodmother, Nature's Prophet, Chen, Terrorblade, Naga Siren, Visage, Wraith King, Lycan, Phantom Lancer, Shadow Shaman.

* Even though Phantom Assassin can easily kill Luna in few strikes, Luna can also do the same to Phantom Assassin if she is not careful.
* An ill-timed and ill-positioned Phantom Strike will make Phantom Assassin an easy target for counter-attack with Eclipse if she does not have Black King Bar available to use and if Phantom Assassin cannot kill Luna fast enough. This can be even better if Luna buys Aghanim's Scepter.
* Moon Glaives can ignore Blur's evasion if Luna attacks an enemy near Phantom Assassin.
* Luna can counter Blur's evasion by buying either Silver Edge, or Monkey King Bar, which are common items on Luna.
* Luna just has to be careful about Fan of Knives from Aghanim's Shard and Coup De Grace, as Fan of Knives can disable Moon Glaives and Lunar Blessing while Coup De Grace can deal serious damage to her even if she is spell immune, though this issue can be solved by buying Ethereal Blade, which is a situational item on Luna.
Additional:
* Even though Phantom Assassin can easily kill Luna in few strikes, Luna can also do the same to Phantom Assassin if she is not careful.
* An ill-timed and ill-positioned Phantom Strike will make Phantom Assassin an easy target for counter-attack with Eclipse if she does not have Black King Bar available to use and if Phantom Assassin cannot kill Luna fast enough. This can be even worse if Luna buys Aghanim's Scepter.
* Moon Glaives can ignore Blur's evasion if Luna attacks an enemy near Phantom Assassin. Aghanim's Shard upgraded Moon Glaives can also reduce damage from Coup De Grace and Moon Glaives Phantom Assassin inflicts on Luna and damage Spirit Phantom Assassin she is close to her. And the Aghanim's Shard upgraded Moon Glaives have true strike for their duration, which renders Blur's evasion insignificant.
* Luna can counter Blur's evasion by buying either Silver Edge, or Monkey King Bar, which are common items on Luna.
* Luna just has to be careful about Fan of Knives from Aghanim's Shard and Coup De Grace, as Fan of Knives can deal health-based damage to Luna and disable Moon Glaives and Lunar Blessing while Coup De Grace can deal serious damage to her even if she is spell immune, though this issue can be partially solved by buying Ethereal Blade, which is a situational item on Luna.

* Luna's Moon Glaives and Lunar Blessing can clear waves of Naga Siren's illusions from Mirror Image.
* Once Naga Siren's illusions are cleared with Aghanim's Shard upgraded Moon Glaives, Eclipse can often finish off Naga Siren before she can escape with Song of the Siren.
* A well-timed Aghanim's Scepter upgraded Eclipse combined with 0.25 Eclipse Lucent Ministun talent can be casted at long range and allow Luna to burst down Naga Siren faster and repetively stun Naga Siren, preventing her from escaping with Song of the Siren and Town Portal Scroll without getting caught in it's range.
* Luna is a natural Black King Bar wielder unlike Naga Siren who barely goes for it, which allows Luna to freely attack Naga Siren during Song of the Siren and potentially get rid of the most of the damage and crowd-control from Naga Siren.
Additional:
* Luna's Moon Glaives and Lunar Blessing can clear waves of Naga Siren's illusions from Mirror Image, especially when combined with Gleipnir and Manta Style. Aghanim's Shard upgraded Moon Glaives can also be used to destroy Naga Siren's illusions and damage the real Naga Siren if they are too close to Luna while also reducing any damage Naga Siren inflicts on Luna for their duration.
* Once Naga Siren's illusions are cleared, Eclipse can often finish off Naga Siren before she can escape with Song of the Siren.
* A well-timed Aghanim's Scepter upgraded Eclipse combined with 0.25 Eclipse Lucent Ministun talent can be casted at long range and allow Luna to burst down Naga Siren faster and repetively stun Naga Siren, preventing her from escaping with Song of the Siren and Town Portal Scroll without getting caught in it's range.
* Luna is a natural Black King Bar wielder unlike Naga Siren who barely goes for it, which allows Luna to freely attack Naga Siren during Song of the Siren and potentially get rid of the most of the damage and crowd-control from Naga Siren.

* Heroes with AoE nukes will clear her illusions in no time, especially if they are percentage-damage-based, like Underlord's Firestorm, Elder Titan's Earth Splitter, Enigma's Midnight Pulse, Zeus's Arc Lightning, Jakiro's Liquid Frost from Aghanim's Shard etc.

* Heroes such as Lone Druid, Tidehunter and Viper can be very problematic for Phantom Assassin because they give her very little time to farm and become scary.

* Fate's Edict cripples many heroes who rely on attacks, such as Phantom Assassin, Sven, or Enchantress, without a dispel or a Black King Bar.

* Heroes with illusions and summons can be hard for Phantom Assassin to deal with, as she lacks any AoE abilities to deal with them without items: Broodmother, Phantom Lancer, Chaos Knight, Lycan, Naga Siren, Shadow Shaman, Visage, Nature's Prophet, Terrorblade, Warlock, Wraith King.

* Many physical-only single-target heroes like Lifestealer, Sven, Wraith King, Phantom Assassin, Templar Assassin can have their damage mitigated by Cold Embrace.

* Heroes with disables that ignore spell immunity will render Phantom Assassin completely useless in teamfights throughout the game: Axe, Enigma, Vengeful Spirit, Doom, Bane, Beastmaster, Pudge, Medusa, Warlock.

* Heroes with illusions and summons can be hard for Phantom Assassin to deal with, as she lacks any AoE abilities to deal with them without items: Broodmother, Phantom Lancer, Chaos Knight, Lycan, Naga Siren, Shadow Shaman, Visage, Nature's Prophet, Terrorblade, Warlock, Wraith King.

* Heroes with long cast animations can be continuously interrupted by Battery Assault: Centaur Warrunner, Jakiro, Leshrac, Naga Siren, Underlord.

* Heroes that can apply early pressure before Phantom Assassin has farm are massive threats: Axe, Viper, Meepo, Jakiro, Pugna, Slark, Venomancer etc.

* Fire Spirits applies a severe attack speed slow, severely hindering Phantom Assassin's damage output.
* Phantom Assassin cannot cast Phantom Strike on Phoenix during Supernova.
Additional:
* While her Phantom Strike does give limited extra attack speed, she cannot use the ability against the Phoenix Sun, and while her Blur may protect her from attacks, Phoenix's strong magical DPS burns away her small health pool quickly, and the attack speed slow makes her unable to fight back (provided she has no source of spell immunity).

* Sand King and Phoenix have many tools to deal with multiple enemies at once, which will work well against a crowd of illusions.

* Heroes that heavily depend on illusions or summons, (Naga Siren, Terrorblade, Phantom Lancer, Lycan,...) are vulnerable to Sleight of Fist and even more so if Ember Spirit has Battle Fury.

* Heroes with illusions and summons can be hard for Phantom Assassin to deal with, as she lacks any AoE abilities to deal with them without items: Broodmother, Phantom Lancer, Chaos Knight, Lycan, Naga Siren, Shadow Shaman, Visage, Nature's Prophet, Terrorblade, Warlock, Wraith King.

* Heroes which rely exclusively on right clicks will struggle somewhat against Blinding Light: Phantom Assassin, Wraith King, Medusa

* Keeper of the Light can stall pushes with Illuminate. This makes him strong against pushing heroes: Terrorblade Naga siren Nature's Prophet and Anti-Mage

* Heroes who are reliant on illusions or summons: Chaos Knight, Broodmother, Naga Siren.

* Heroes that rely on escapes to stay alive can be caught and locked down for a long time: Queen of Pain, Phantom Assassin

* Heroes with long-lasting, undispellable debuffs will pinpoint the true Naga Siren: Spirit Breaker, Bloodseeker, Witch Doctor.

* In early to mid stage, Silence is also a great way to counter escape oriented heroes such as Anti-Mage, Queen of Pain, and Phantom Assassin to prevent them from escaping, provided that they don't have any basic dispels.

* Heroes that can apply early pressure before Phantom Assassin has farm are massive threats: Axe, Viper, Meepo, Jakiro, Pugna, Slark, Venomancer etc.

* Hex abilities prevent attacking, ability and item usage, which is a severe problem for Phantom Assassin as it prevents her from using Black King Bar, the one item that helps protect her against the aforementioned dangers. Doom and Shadow Demon with Aghanim's Scepter also disables Phantom Assassin's Evasion and Critical Strike, removing much of her damage and survivabaility: Doom, Disruptor with Aghanim's Scepter, Dazzle with Aghanim's Shard

* Heroes with disables that ignore spell immunity will render Phantom Assassin completely useless in teamfights throughout the game: Axe, Enigma, Vengeful Spirit, Doom, Bane, Beastmaster, Pudge, Medusa, Warlock.

* Heroes who rely on physical damage output to be effective will fare badly against Muerta's Pierce the Veil: Phantom Assassin, Terrorblade, Drow Ranger, Lifestealer, Anti-Mage, Alchemist, Lycan, Clinkz, Sniper.

* Heroes whose attacks can affect multiple enemies at once will clear Naga Siren's illusions. Such heroes include Sven, Magnus, Dragon Knight, Luna, Medusa, Templar Assassin, Gyrocopter, Muerta.

* In general, Brewmaster's Cinder Brew and Thunder Clap makes him good against physical damage carries: Ursa, Clinkz, Faceless Void, Troll Warlord, Templar Assassin, Phantom Assassin.

* Doom with the {ValueColor:1|Doom applies Break|25tal} {Symbol:Talent} talent can be useful against heroes with troublesome passive skills while also disabling them for a long time: Phantom Assassin, Enchantress, Huskar, Underlord.

* Heroes with illusions and summons can be hard for Phantom Assassin to deal with, as she lacks any AoE abilities to deal with them without items: Broodmother, Phantom Lancer, Chaos Knight, Lycan, Naga Siren, Shadow Shaman, Visage, Nature's Prophet, Terrorblade, Warlock, Wraith King.

* Blade Fury offers good AoE damage to clear illusions and can hurt the real Naga Siren as well if she chooses to blend in the illusions. Diffusal Blade does nothing to Juggernaut either when he uses Blade Fury.
* Aghanim's Shard upgraded Blade Fury along with Lv 20 DPS talent will shred all illusions almost instantly, especially when combined with Mjollnir, a common item for Juggernaut.

* Tinker can use Laser to save an ally or himself from Phantom Assassin's initiate Phantom Strike due to the blind, forcing her to use a Black King Bar to effectively initiate, Tinker can also use Warp Flare one he buys Aghanim's Shard to reverse Phantom Strike's blinking with Phantom Strike.
* Tinker almost never uses his physical attack, relying on his spell-spamming to deal damage which ignores Blur's Evasion
* Defense Matrix prevents Coup de Grace from triggering.

* Enfeeble greatly reduces Phantom Assassin's attack damage, and if her attack damage is weak, Coup De Grace will also suffer from attack damage reduction as well. Enfeeble also reduces cast range of Phantom Assassin's abilities, making her unable to harass with Stifling Dagger and to use Phantom Strike at longer distances.
* Nightmare and Fiend's Grip can ground Phantom Assassin, who normally blinks around with Phantom Strike, and stop her from outputting damage.
* Phantom Assassin's low health pool early on makes her susceptible to {A|Brain Sap|Bane
Additional:
* Enfeeble greatly reduces Phantom Assassin's attack damage, and if her attack damage is weak, Coup De Grace will also suffer from attack damage reduction as well. Enfeeble also reduces any healing Phantom Assassin receives, making her unable to heal herself with Phantom Strike, and it also reduces cast range of Phantom Assassin's abilities, making her unable to harass with Stifling Dagger and to use Phantom Strike at longer distances.
* Nightmare and Fiend's Grip can ground Phantom Assassin, who normally blinks around with Phantom Strike, and stop her from outputting damage, even with Black King Bar.
* Phantom Assassin's low health pool early on makes her susceptible to Brain Sap and Fiend's Grip's heavy nuke damage.

* Avalanche and Toss combo makes short work of Mirror Image's illusions.
* Tiny's cleave with Tree Grab and area of effect damage with Tree Volley will easily wipe out illusions.

* Slark's Pounce allows him to close the gap on Phantom Assassin and prevent her from escaping with Phantom Strike.
* As a hero who typically builds Silver Edge, Slark can use it to disable Phantom Assassin's Blur and Coup de Grace, thus taking down her attack evasion and drastically reducing her damage output.
* Because Phantom Assassin is always reliant on critical strikes, Slark will have plenty of time to escape with Pounce, Shadow Dance and Silver Edge (provided that he purchased it already).
* Depth Shroud from Aghanim's Shard will allow Slark to save both, himself and his allies from Phantom Assassin with Shadow Dance, and to freely fightback against her without removing invisibility upon attacking.
* Essence Shift is much more harmful for Phantom Assassin than for other heroes, as losing the agility means that her physical damage will be also reduced, which can also weaken Coup de Grace if Slark manages to steal lots of agility from her.
* Overall, any attempt for Phantom Assassin to take down Slark will hurt her more than Slark.
Additional:
* Slark's Pounce allows him to close the gap on Phantom Assassin and prevent her from escaping with Phantom Strike.
* As a hero who typically builds Silver Edge, Slark can use it to disable Phantom Assassin's Blur and Coup de Grace, thus taking down her attack evasion and drastically reducing her damage output.
* Because Phantom Assassin is always reliant on critical strikes, Slark will have plenty of time to escape with Pounce, Shadow Dance and Silver Edge (provided that he purchased it already).
* Depth Shroud from Aghanim's Shard will allow Slark to save both, himself and his allies from Phantom Assassin with Shadow Dance, and to freely fightback against her without removing invisibility upon attacking.
* Essence Shift is much more harmful for Phantom Assassin than for other heroes, as losing the agility means that her physical damage will be also reduced, which can also weaken Coup de Grace if Slark manages to steal lots of agility from her.
* Overall, any attempt for Phantom Assassin to take down Slark will hurt her more than Slark.

* While Phantom Assassin can kill Skywrath Mage in a few strikes, Skywrath Mage can also do the same to her if she is not careful.
* Arcane Bolt's long range and low cooldowns allows Skywrath Mage to severely harass Phantom Assassin in lane.
* Ancient Seal prevents Phantom Assassin from escaping or engaging with Phantom Strike.
* Mystic Flare's heavy magical damage nukes Phantom Assassin down quickly during the early to mid game.
Additional:
* While Phantom Assassin can kill Skywrath Mage in a few strikes, Skywrath Mage can also do the same to her if she is not careful.
* Arcane Bolt's long range and low cooldowns allows Skywrath Mage to severely harass Phantom Assassin in lane.
* Ancient Seal prevents Phantom Assassin from escaping or engaging with Phantom Strike.
* Mystic Flare's heavy magical damage nukes Phantom Assassin down quickly during the early to mid game.

* Heroes who can delivers a big chunk of damage in few hits will find themselves struggle against Templar Assassin's Refraction: Sven, Phantom Assassin, Ursa, Wraith King, Lifestealer

* Heroes whose attacks can affect multiple enemies at once will clear Naga Siren's illusions. Such heroes include Sven, Magnus, Dragon Knight, Luna, Medusa, Templar Assassin, Gyrocopter, Muerta.

* Heroes with single-target abilities will be overwhelmed by Lycan and his summons: Wraith King, Bane, Phantom Assassin.

* Heroes with illusions and summons can be hard for Phantom Assassin to deal with, as she lacks any AoE abilities to deal with them without items: Broodmother, Phantom Lancer, Chaos Knight, Lycan, Naga Siren, Shadow Shaman, Visage, Nature's Prophet, Terrorblade, Warlock, Wraith King.

* Heroes with illusions and summons can be hard for Phantom Assassin to deal with, as she lacks any AoE abilities to deal with them without items: Broodmother, Phantom Lancer, Chaos Knight, Lycan, Naga Siren, Shadow Shaman, Visage, Nature's Prophet, Terrorblade, Warlock, Wraith King.

* 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.

* With Aghanim's Scepter upgraded Infest, Lifestealer can use it on enemy heroes to attack them and disarm them from inside, even if they are spell immune, which can give him the edge over the heroes he's weak against like Ursa, Phantom Assassin, Terrorblade or Troll Warlord.

* Heroes that can apply early pressure before Phantom Assassin has farm are massive threats: Axe, Viper, Meepo, Jakiro, Pugna, Slark, Venomancer etc.

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

* Heroes who just want to farm and avoid Lone Druid early will find it very hard to do so when he starts knocking on towers: Templar Assassin, Phantom Assassin, Ember Spirit, Morphling.

* Hex abilities prevent attacking, ability and item usage, which is a severe problem for Phantom Assassin as it prevents her from using Black King Bar, the one item that helps protect her against the aforementioned dangers. Doom and Shadow Demon with Aghanim's Scepter also disables Phantom Assassin's Evasion and Critical Strike, removing much of her damage and survivabaility: Doom, Disruptor with Aghanim's Scepter, Dazzle with Aghanim's Shard

* Dazzle can instantly destroy all of Naga Siren's illusions from Mirror Image with Aghanim's Shard upgraded Poison Touch used on her or any of her illusions.

* Heroes who are illusion based, or even heroes who frequently build Manta Style can be cleared quickly by Pangolier's high damage, or lose their damage ouput because of Lucky Shot: Chaos Knight, Naga Siren

* Heroes with disables that ignore spell immunity will render Phantom Assassin completely useless in teamfights throughout the game: Axe, Enigma, Vengeful Spirit, Doom, Bane, Beastmaster, Pudge, Medusa, Warlock.

Additional:
* If Phantom Assassin jumps on Pudge first with Phantom Strike, she will be a very easy target for Pudge's Meat Hook and Dismember combo.
* Even though it can deal damage based on Pudge's max health, Fan of Knives from Aghanim's Shard cannot disable Pudge's Flesh Heap as Flesh Heap is one of the few passive abilities that cannot be disabled by break.
* Both Meat Hook and Dismember ignore spell immunity which allows Pudge to disable Phantom Assassin even while she has Black King Bar active.
* Pudge occassionally buys armor items like Blade Mail, which in combination with many stacks from Flesh Heap can make Phantom Assassin have little effect against Pudge.

* Heroes with illusions and summons can be hard for Phantom Assassin to deal with, as she lacks any AoE abilities to deal with them without items: Broodmother, Phantom Lancer, Chaos Knight, Lycan, Naga Siren, Shadow Shaman, Visage, Nature's Prophet, Terrorblade, Warlock, Wraith King.

* With Bloodthorn, Clinkz becomes a strong counter to heroes who rely on evasion and blind such as Windranger, Phantom Assassin, Troll Warlord and Keeper of the Light.

* Heroes who rely on physical damage are easily negated by Ghost Shroud: Phantom Assassin, Wraith King, Juggernaut.

* Heroes with heavy early and mid-game magical damage are also problematic for Phantom Assassin due to being able to easily kill her before she can gain an item advantage over them: Lina, Necrophos, Nyx Assassin, Gyrocopter, Jakiro, Death Prophet.

* Heroes with long-lasting, undispellable debuffs will pinpoint the true Naga Siren: Spirit Breaker, Bloodseeker, Witch Doctor.

* Heroes whose attacks can affect multiple enemies at once will clear Naga Siren's illusions. Such heroes include Sven, Magnus, Dragon Knight, Luna, Medusa, Templar Assassin, Gyrocopter, Muerta.

* Purification and Hammer of Purity can easily catch Phantom Assassin once she jumps with Phantom Strike in to attack.
* Heavenly Grace can be used to dispel slow from Stifling Dagger, and disables from the items Phantom Assassin relies on.
* Phantom Assassin depends entirely on physical attacks and her damage output is 100% physical. Therefore, since she has no any sources of magical damage output and hates going for items that deal magical damage like Dagon, Ethereal Blade and Revenant's Brooch, Guardian Angel will render her completely useless.
* Purification, Heavenly Grace and Guardian Angel can be used to save an allied hero before Phantom Assassin can finish them off with Coup De Grace.
Additional:
* Purification and Hammer of Purity can easily catch Phantom Assassin once she jumps with Phantom Strike in to attack.
* Heavenly Grace can be used to dispel slow from Stifling Dagger, and disables from the items Phantom Assassin relies on.
* Phantom Assassin depends entirely on physical attacks and her damage output is 100% physical. Therefore, since she has no any sources of magical damage output and hates going for items that deal magical damage like Dagon, Ethereal Blade and Revenant's Brooch, Guardian Angel will render her completely useless.
* Purification, Heavenly Grace and Guardian Angel can be used to save an allied hero before Phantom Assassin can finish them off with Coup De Grace.

* Heroes with illusions and summons can be hard for Phantom Assassin to deal with, as she lacks any AoE abilities to deal with them without items: Broodmother, Phantom Lancer, Chaos Knight, Lycan, Naga Siren, Shadow Shaman, Visage, Nature's Prophet, Terrorblade, Warlock, Wraith King.

* Hex abilities prevent attacking, ability and item usage, which is a severe problem for Phantom Assassin as it prevents her from using Black King Bar, the one item that helps protect her against the aforementioned dangers. Doom and Shadow Demon with Aghanim's Scepter also disables Phantom Assassin's Evasion and Critical Strike, removing much of her damage and survivabaility: Doom, Disruptor with Aghanim's Scepter, Dazzle with Aghanim's Shard