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

* Charge of Darkness can be used to escape or counter-initiate against a Relocate gank.
* Greater Bash and Nether Strike is devastating due to Io's low armor, and can even knock it away from tethered target.

* Cold Embrace can render the extra attack speed from Overcharge meaningless.
* Splinter Blast and Winter's Curse are very affective against Io, as it has to stay close to its tethered hero.

* Many physical-only single-target heroes like Lifestealer, Sven, Wraith King, Phantom Assassin etc.

* Phantom Strike's extra attack speed causes Phantom Assassin to proc Counter Helix more often. Using it on Axe also makes Phantom Assassin an 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.
Additional:
* Jumping in with Phantom Strike makes Phantom Assassin an exceptionally easy target for Berserker's Call.
* The bonus attack speed from Phantom Strike also means that Phantom Assassin will proc Counter Helix numerous times.
* Black King Bar is generally useless against Axe's abilities and item build, as Black King Bar doesn't prevent Axe from finishing Phantom Assassin off with Culling Blade. It also doesn't work against Berserker's Call and Counter Helix.
* Blade Mail is an item that Axe purchases every game, and it can be used to turn Phantom Assassin's critical strikes against herself. The situation becomes even worse if she's affected by Berserker's Call, as she has no way to stop attacking.

* Heroes that are hard to gank: Axe, Death Prophet, Phantom Lancer

* Doom, Disruptor with Aghanim's Scepter, and hex abilities all prevent 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.

* Glimpse directly negates Relocate.
Additional:
* Disruptor can always Glimpse back Io or his target after he Relocated nearby.
* Even better, thanks to the indicator on the ground, you can even preemptively drop Static Storm and Kinetic Field on the spot they will relocate to.
* Thunder Strike and Glimpse are also good tools to bring back an Io that Tethered away in the fog of war.

* Heroes that are hard to gank: Axe, Death Prophet, Phantom Lancer

* 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 are hard to gank: Axe, Death Prophet, Phantom Lancer

* Heroes with illusions and summons can be hard for Phantom Assassin to deal with, as she lacks any AoE abilities to deal with them: Broodmother, Phantom Lancer, Chaos Knight.

* Strafe and Searing Arrows allow Clinkz to quickly kill Io due to its low armor.

* 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.

* Phantom Assassin's single target abilities make her very helpless against swarms of spiderlings.
* Because Phantom Assassin is always reliant on critical strikes, Broodmother will usually have enough time to use Spin Web to save herself.
* Aside from Spin Web, Incapacitating Bite can cripple her due to being reliant on physical attacks and critical strikes.
Additional:
* Phantom Assassin's single target abilities make her very helpless against swarms of Spiderlings.
* Because Phantom Assassin is always reliant on critical strikes, Broodmother will usually have enough time to use Spin Web to save herself.
* Incapacitating Bite cripples her due to reliant on physical attacks.

* Black King Bar is useless, since all of the Spectre's abilities go through spell immunity,
* Phantom Assassin's Blur cannot evade Desolate because its damage is a separate damage instance and is applied before the attack hits.
* Spectre's high durability provided by Dispersion and damage block items makes her one of the hardest carries to take down.
Additional:
* Dispersion makes it hard for Phantom Assassin to burst down Spectre while also reflecting back Phantom Assassin's high burst damage against herself.
* Desolate ignores the evasion from Blur.
* Black King Bar is useless against Spectre as all of her skills pierce spell immunity.

* Thirst allows Bloodseeker to see where Io relocated to, should either Io or the tethered hero have low health.
* Rupture forces Io to stay in place, preventing it from using the Tether bonus movement speed to escape.

* 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 Brain Sap and Fiend's Grip's heavy nuke damage.
Additional:
* Nightmare's lengthy duration prevents Phantom Assassin from finishing off a target enemy hero.
* Fiend's Grip can disable Phantom Assassin, even through spell immunity.

* Living Armor can be used to save a hero from a Relocate gank.

* Ignite has long duration damage-over-time and prevents Io from healing his Tethered ally.

* 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.

* Phantom Assassin's Blur will be useless if Windranger managed to get Monkey King Bar or Bloodthorn, and other than Stifling Dagger, Phantom Assassin has no abilities that can bypass Windrun.
* Focus Fire can still deal considerable damage despite Blur's evasion due to the increased attack speed.

* 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.
Additional:
* Static Link greatly lowers the damage output from Coup de Grace, hindering Phantom Assassin's main source of scaling.
* Eye of the Storm strikes cannot be evaded by Blur.

* 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.
Additional:
* 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 magic burst.
* Timbersaw can easily escape from Phantom Assassin thanks to his Timber Chain.

* 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.
Additional:
* Whirling Axes (Melee) makes it hard to land a Coup de Grace.
* Troll Warlord often buys Silver Edge and Monkey King Bar, the items that greatly counters Phantom Assassin.
* 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.

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

* Lightning Storm will usually hit both Io and its tethered target since both will be close enough for the lightning to jump.
* Diabolic Edict and Pulse Nova hit all units near Leshrac, meaning he can do colossal damage to Io and its tethered target.
Additional:
* Lightning Storm will usually hit both Io and his Tethered target since both will be close enough for the lightning to jump. It can then be followed up by Split Earth.
* Diabolic Edict and Pulse Nova hit all units near Leshrac, meaning he can do colossal damage to Io and his Tethered target.

* Retaliate deals damage to Phantom Assassin for every attack and Stifling Dagger thrown at Centaur.
* Blur cannot evade Double Edge.
Additional:
* Retaliate turns Phantom Assassin's attacks against herself, as he deals damage with every hit taken, and his big health pool makes sure that a lot of hits will be needed.
* If Centaur Warrunner gets the jump on Phantom Assassin first, she will be unable to activate Black King Bar and might be burst down with the help of his Double Edge.
* Stampede can save an ally under attack by Phantom Assassin, offsetting the slow from Stifling Dagger. If he owns an Aghanim's Scepter, he can prevent a low-health ally from being killed in one crit.

* Despite her high mobility, Hex or Earth Spike can lock Phantom Assassin down and make her vulnerable.
* Although she has high evasion through Blur, Phantom Assassin has a rather low health pool, making her weak to Lion's magical burst.
Additional:
* Hex and Earth Spike's fast cast animations easily catches Phantom Assassin when she jumps in to attack.
* Finger of Death often ends Phantom Assassin before she can do anything in the early to mid game.

* Slark's Pounce allows him to close the gap on Phantom Assassin and prevent her from escaping with Phantom Strike.
* As a hero who always goes for the Silver Edge and Abyssal Blade Slark can use it to disable Phantom Assassin and her Blur and Coup de Grace, drastically reducing her damage output and ability to evade attacks, and also preventing her from acting.
* Phantom Assassin's Coup de Grace requires Random Number Generation in order to proc, which gives Slark more than enough time to escape and recover himself.

* Morphling's naturally high armor thanks to his high agility makes it hard for Phantom Assassin to take him down with Coup de Grace.
* Phantom Assassin is vulnerable to magical damage, falling easily to Adaptive Strike + Ethereal Blade combo.
Additional:
* Morphling's high armor serves as a direct counter to Phantom Assassin, causing her attacks to do far less damage. She is also very vulnerable to burst damage, and can be brought down quickly using his Ethereal Blade and Adaptive Strike combo.

* 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.

* Grimstroke can catch Io and his ally easily with SoulBind as Io has a tendency to tether himself with an ally frequently.
* Io is highly vulnerable to disables. Hence, Grimstroke's Phantom's Embrace is a great ability to hinder Io's potential.
Additional:
* Soulbind can target both Io and its Tethered ally, allowing Grimstroke and his team to target both with single target spells. Should Io try to Relocate, Phantom's Embrace can stop its channel to prevent escape.

* Quill Spray is very effective against Io, as it has very low armor and has to stay close to the fight to not break its Tether.

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

* Heroes with magical burst damage can often kill Phantom Assassin before she gets to do much: Necrophos, Nyx Assassin, Gyrocopter.

* 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.

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

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

* 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.

* 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.

* Fragile heroes: Bounty Hunter has decent nuking capabilities with Shiruken Toss and Jinada thus making fragile heroes easy picks for ganking. Few examples of such heroes are:Crystal Maiden, Pugna, Skywrath Mage, Io, Witch Doctor, etc.

* Heroes with illusions and summons can be hard for Phantom Assassin to deal with, as she lacks any AoE abilities to deal with them: Broodmother, Phantom Lancer, Chaos Knight.

* Heroes who rely strongly on melee physical damage will fare badly against Omniknight's Guardian Angel: Sven, Phantom Assassin, Juggernaut, Dragon Knight, Lycan, Ursa, Troll Warlord

Additional:
* Purification easily catches Phantom Assassin when she jumps in to attack.
* Guardian Angel renders Phantom Assassin useless, as she depends entirely on physical attacks.

* Squishy heroes (Io, Crystal Maiden, Lina...), as Earth Spirit can deal tons of damage with Magnetize.

* 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.

* 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

* 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.

* Heroes that can easily bypass Io's allies to get to Io: Riki, Tusk, Clinkz, Sniper

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

Additional:
* High armor thanks to Dragon Blood makes it difficult for Phantom Assassin to burst down Dragon Knight, as she deals 100% physical damage.
* Dragon Tail stuns Phantom Assassin as soon as she initiates, preventing her from gaining bonus attack speed.
* Dragon Knight is one of the few heroes who can safely solo lane against Phantom Assassin alongside a support.

* Heroes who rely on physical damage will suffer from Laser: Phantom Assassin, Wraith King, Huskar.

Additional:
* The blind from Laser can render Phantom Assassin useless if she is not protected by Black King Bar.
* Tinker is a natural Scythe of Vyse carrier and can permanently disable Phantom Assassin, not giving her chance to activate Black King Bar if she has it.

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

* Doom, Disruptor with Aghanim's Scepter, and hex abilities all prevent 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.

* Heroes with magical burst damage can often kill Phantom Assassin before she gets to do much: Necrophos, Nyx Assassin, Gyrocopter.

* 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.

* Lucent Beam can cancel Tether and Relocate.
* Moon Glaives and Eclipse make short work of Io and its tethered ally.

* Nethertoxin breaks Phantom Assassin's passive skills.
* Viper Strike goes through Black King Bar.

* Ice Blast prevents Io from healing the target.
Additional:
* Ice Blast prevents Io from healing an ally with Tether and prevents healing from Overcharge
* Io is a common Mekansm builder which is useless if he is affected by Ice Blast.

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

* Heroes with low armor and little mobility, like Huskar, Io, etc. will also have an unfortunate fate.