* 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.

* Cold Embrace mitigates Primal Roar's single-target initiation on allies.
* Winter's Curse can turn Beastmaster's summons and Inner Beast against his teammate.
Additional:
* Beastmaster's summons and Inner Beast are very useful to attack his cursed teammate.
* Cold Embrace effectively mitigates Primal Roar's single-target initiation on allies.

* Heroes who summon multiple units that are not spell immune. Nature's Prophet,Lycan,Beastmaster

* 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.

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

* 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.

* Aphotic Shield effectively nullifies Primal Roar's single-target initiation on allies.
* Even being initiated by Primal Roar, Borrowed Time can make Abaddon extremely difficult to kill.
Additional:
* Primal Roar can be instantly dispelled by Aphotic Shield.
* The debuffs from Wild Axes and Poison from Call of the Wild: Boar can also be dispelled by Aphotic Shield.

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

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

* False Promise effectively nullifies Primal Roar's single-target initiation on allies.
* Purifying Flames kills Beastmaster's Hawk instantly and Boar with two casts.

* 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.

* 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.

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

* 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.

* Having many summons out will cause Echo Slam to deal extra damage.

* Lich's Chain Frost forces Io to give up providing buff to his ally with Tether or suffer devastating damage with his tethered ally.
* Lich could easily use Sinister Gaze to disable Io from getting away with Tether or Relocate.

* Reactive Armor is very effective against Beastmaster's summons during laning stage and entire game.
* Timbersaw can quickly clear Beastmaster's summons with his nukes.

* 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.

* Untouchable negates Inner Beast's attack speed bonus, making her hard to kill even if stunned by Primal Roar.
* Enchantress can also take control of Beastmaster's summons.
Additional:
* Enchant can control Beastmaster's boars, mitigating his effectiveness during the laning stage and teamfights.

* Illuminate clears Beastmaster's summons and is effective against his push.

* 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.

* Chen can take control of Beastmaster's summons, especially Necronomicon units.

Additional:
* Chen can take control of the Boar from Call of the wild Boar at any time.

* Single-target disablers will have difficulty locking down a Chaos Knight with Phantasm active: Bane, Beastmaster, Bloodseeker, Clockwerk, Doom, Shadow Shaman.

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

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

* Heroes with Linken's Sphere as core item: Weaver, Morphling, Medusa.

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

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

* Heroes with strong dispels can remove Primal Roar's stun: Abaddon, Slark, Oracle.

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

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

* Heroes with Linken's Sphere as core item: Weaver, Morphling, Medusa.

* Heroes with Linken's Sphere as core item: Weaver, Morphling, Medusa.

* Heroes with AoE abilities are a bane to Beastmaster's summons: Storm Spirit, Magnus, Pangolier.

* 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.

* Take Aim and Assassinate allow Sniper to reach Io even if it stays in the backline.

* Phantom Strike allows Phantom Assassin jump directly to Io.
* Coup de Grace makes short work of Io's low health and armor.