* Being a cast-oriented hero, Ezalor will suffer from all of Silencer's abilities.
* Global Silence is a guaranteed lengthy silence which will render Ezalor useless in a teamfight.
* Arcane Curse and Last Word are good against any caster, since they are extremely potent.
* However, it should be worth mentioning that a smart Ezalor will buy Eul's Scepter of Divinity to dispel Silencer's abilities. Combined with the level 20 talent (Chakra Magic applies a basic dispel), Ezalor can purge Silencer's abilities off allies and himself alike.

* Bristleback will not be able to cast Viscous Nasal Goo or Quill Spray while silenced, effectively blocking a major part of the hero's damage and preventing Warpath charges from stacking.
* Arcane Curse slows Bristleback down and lasts longer the more abilities he uses. On the other hand, if he doesn't use any abilities, he will begin to lose Warpath charges.
Additional:
* Arcane Curse stacks every time Bristleback uses an ability, forcing him to stop spamming his abilities, or take heavy health degeneration.
* Glaives of Wisdom steals intelligence both permanently and temporarily, causing mana issues for Bristleback.
* Last Word and Global Silence stops Bristleback from using his abilities altogether.

* Infernal Blade deals scaling damage and is useful against high HP targets such as Bristleback.
* Doom prevents Bristleback from casting his two low cooldown abilities, which then prevents him from utilizing Warpath.
* If Doom gets an Aghanim's Scepter, he can disable Bristleback and Warpath, taking away much of his durability and damage potential in team fights.
Additional:
* Infernal Blade deals scaling damage and is useful against high health targets such as Bristleback.
* Doom disables Bristleback's low cooldown abilities, preventing him from triggering Warpath. With Aghanim's Scepter, it also breaks Bristleback's passive, rendering him more vulnerable.

* Heroes with silences: Puck, Doom, Riki.

* Mana Drain is a headache for Bristleback to deal with during the laning stage, as it denies him the ability to get last hits with Quill Spray.
* Finger of Death deals high damage to Bristleback, and only triggers his passive once.

* Mana Drain is very effective against heroes that have mana burn abilities such as Anti-Mage, Nyx Assassin and Keeper of the Light.

* Being an intelligence caster hero, Ezalor usually has a high mana pool and low health and armor, making him a prime target for Mana Void
* Ezalor's Illuminate damage and Solar Bind's magic resistance reduction are greatly reduced thanks to Counterspell. Counterspell can also block and reflect Solar Bind if timed properly.
* Anti-Mage usually is not hampered by Solar Bind or Will-O-Wisp thanks to Blink.
* However, despite all of this, if Keeper of the Light is played carefully and tops off his team's mana at all times, Anti Mage will not be able to get off a good Mana Void.

* Mana Break quickly eats away at Bristleback's small mana pool, preventing him from spamming Viscous Nasal Goo and Quill Sprays.
* Bristleback has no innate mobility. Bristleback is easily kited by Blink, ignoring the protection from Bristleback.
Additional:
* Mana Break removes both a percentage and flat amount of your mana, preventing you from using abilities in the lane.
* Blink Anti-Mage has very high mobility with this skill, and can easily escape from you since you have no way to prevent his blink. He can also use this offensively to get in front of you during fights.

* Press the Attack can dispel Blinding Light or Solar Bind from a hero.
* Duel can be used to instantly take Keeper of the Light out of a team-fight.

* Duel makes Bristleback fight Legion Commander face to face, forcing him to take full damage.
* Press the Attack dispels the slow from stacks of Viscous Nasal Goo.
Additional:
* When dueled, Bristleback will have to face Legion head on, not allowing his passive Bristleback to come into effect.

* Undying's Decay is a dangerous ability against Bristleback, as it makes him more vulnerable and reduces his tankiness.
* Undying's Tombstone together with Flesh Golem can slow Bristleback down significantly.

* Heroes with dispels: Legion Commander, Oracle, Slark, Phantom Lancer

* Essence Shift allows Slark to hit bristleback freely whether on the front or back, stealing attributes and make bristleback much less tanky.
* Pounce can be used to disengage and recover loss HP with his ultimate passive, and can return to fight in a short period while bristleback is already injured and got some of his attributes stolen.
* Dark Pact makes it near impossible to keep Viscous Nasal Goo debuff on slark.
* Although Dark Pact cannot dispel Quill Spray, means Slark will still receive quill stack damage even if he uses Shadow Dance before.
* Slark builds Silver Edge in almost every game, an item that greatly counter birstleback.

* Guardian Sprint allows Slardar to outrun Bristleback, even when slowed by Viscous Nasal Goo.
* Corrosive Haze's armor reduction makes Bristleback much less tanky.

* Keeper of the Light's Aghanim's Scepter upgrade loses much of its power, due to Night Stalker being able to reduce the duration of daytime by a lot.
Additional:
* Crippling Fear prevents Keeper of the Light from using his spells to keep his team alive during team-fights.
* Dark Ascension is very strong against Keeper of the Light, as it allows Night Stalker to jump the backline and quickly kill the squishy Ezalor, especially when combined with the slow from Void.

* Shukuchi gets Weaver in front of Bristleback, negating the protection from the Bristleback passive.
* Weaver's mana break talent depletes Bristleback's mana pool, preventing him from spamming abilities.

* Blood Rite makes Ezalor chose between getting off Illuminate or getting silenced for a while, as Illuminate is a channeled ability.
* Blood Rite's silence can completely take Ezalor out of a teamfight, as he relies on his abilities to be useful.
* Keeper of the Light's only mobility source, his high movement speed (via his high base movement speed and through spirit form), is entirely countered by Rupture.

* Sharpshooter deals massive damage to Bristleback and applies a high duration disable on his passive.
* Bushwhack and Scurry can be used to easily kite Bristleback.
Additional:
* Bristleback and Warpath can be disabled by Hoodwink's Sharpshooter ability for a long period of time, reducing his both offense and defense.
* Scurry and Bushwhack can be used to kite bristleback.

* Eye of the Storm melts Bristleback's armor, and makes him much less tanky.
* Static Link can completely drain Bristleback's bonus damage from Warpath.
Additional:
* Eye of the Storm melts Bristleback's armor, and makes him much less tanky.
* Static Link can completely drain Bristleback's bonus damage from Warpath.
* Storm Surge allows Razor to outdistance Bristleback, even with a few stacks of Viscous Nasal Goo on him, Also, if Razor has his Shard, but Bristalback does not, Viscous Nasal Goo will deal damage to Bristalback every time he uses it, And normally, it won't be affected by Bristlebacks Passive, as Bristleback will face him to cast it.

* Phantom's Embrace silences Viscous Nasal Goo and Quill Spray.
* Ink Swell stuns Bristleback and gets allies in position faster with increased movement speed to attack his front, countering his passive ability.

* Whirling Death deals damage as well while reducing 15% of Bristleback's strength, which reduces Bristleback's tankiness.
* Reactive Armor can sustain through multiple Viscous Nasal Goo and Quill Spray stacks.
* Timber Chain makes it hard for Bristleback to slow down Timbersaw with Viscous Nasal Goo.

* 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.

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

Additional:
* 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.

* Tanky melee heroes that can easily be kited, which allows Outworld Destroyer to deal heavy damage with Arcane Orb from a distance: Sven, Underlord, Bristleback.

Additional:
* Sanity's Eclipse only triggers Bristleback's passive once, and deals high damage against Bristleback's low intelligence.
* Outworld Destroyer's high burst damage is not negated by Bristleback's passive, So even if Bristleback turns his back on Outworld, Outworld Destroyer can decimate Bristleback quickly,
* If Bristleback attempts to flee, or tries to close the gap, Outworld can banish him with Astral Imprisonment, both reducing Bristlebacks much needed mana, and allowing Outworld to move in front of him, forcing him to take the full damage from his spells, This will also allow Outworld to land a devasting Sanity's Eclipse, without it being reduced by Bristleback's passive,

* Heroes that withstand damage like Timbersaw, Bristleback, Dragon Knight and others will have their durability largely reduced when hit by an Ice Blast due to the risk of shattering.

* Heroes with hastes: Dark Seer, Lycan

* Heroes with high health especially Strength heroes will take more damage on Sun Ray: Axe, Pudge, Bristleback, Mars.

* Any hero who lanes very poorly will struggle with Primal Beast's potential snowball in the very early levels, like Keeper of the Light, Luna, Templar Assassin...

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

* Heroes that can jump and kill him: Meepo, Clinkz, Templar Assassin

* Heroes who deal single instance burst damage will only proc Bristleback once: Lina, Lion.

* Heroes with teleports to escape Solar Blind and Will-O-Wisp: Phantom Assassin, Puck, Queen of Pain, Storm Spirit

* Batrider's turn rate slow from Sticky Napalm makes it harder for Bristleback to keep his back towards the enemy.

* Heroes with teleports to escape Solar Blind and Will-O-Wisp: Phantom Assassin, Puck, Queen of Pain, Storm Spirit

* Heroes that lose a great amount of their tankiness and become easier to finish off: Bristleback, Spectre, Phantom Assassin, Enchantress, Dragon Knight.
* Once you have an Aghanim's Scepter, Shadow Demon instantly reaches a new power spike and becomes a counter for a variety of heroes that have strong passives.
* Heroes that lose a great amount of their tankiness and become easier to finish off: Bristleback, Spectre, Phantom Assassin, Enchantress, Dragon Knight.
* Heroes that lose a great amount of damage output and become less threatening: Phantom Assassin, Sven, Slark, Phantom Lancer.
* You can always stack camps and farm the scepter with Shadow Poison.

* Juggernaut's Healing Ward keeps his team healthy even when pushing against Keeper of the Light's Illuminate.
* Blade Fury can dispel Blinding Light, as well as dodge an incoming Illuminate. Juggernaut can attack towers during Blade Fury, so he can dodge an Illuminate without having to stop pushing.
* Should Keeper of the Light obtain Will-o-Wisp through purchasing an Aghanim's Scepter, Juggernaut can make quick work of Ignis Fatuus without being interrupted by its pull.
* Keeper of the Light has low health, low armor, and no natural defense against Blade Fury.
Additional:
* Blade Fury allows him to be immune to all of Ezalor's abilities.
* Healing Ward heals his entire team, mitigating Ezalor's weak magical burst damage.

* Time Dilation while Quill Spray and Viscous Nasal Goo are on cooldown will make these abilities unusable for a long time, rendering Bristleback nearly useless.
* Bristleback cannot turn inside the Chronosphere, which makes it easy to attack him from the front, completely bypassing his passive damage reduction.
Additional:
* Time Dilation prevents Bristleback from spamming his low-cooldown abilities, greatly reducing his damage and effectiveness.
* Chronosphere allows allies to reposition and hit Bristleback from the front, bypassing his defensive bonus from behind.
* Bristleback has no way to prevent Void from using Time Walk.

* Nethertoxin disables Bristleback and prevents Warpath from building stacks. Besides losing his defensive passive, Bristleback also loses his ability to build up damage over lengthy battles.
* Viper can perpetually kite Bristleback with Poison Attack and Viper Strike.
Additional:
* Nethertoxin disables Bristleback's passive.
* Viper Strike and Poison Attack slow down Bristleback's movement speed so he's unable to get out from Nethertoxin.

* Heartstopper Aura deals percentage-based damage flagged as HP removal, so it is not reduced by Bristleback, nor does it trigger passive Quill Sprays.
* Reaper's Scythe is very effective against Bristleback not only due to its percentage-based damage, but rather because it first stuns and then deals its damage, allowing Necrophos to position in front of Bristleback in time.
Additional:
* Reaper's Scythe and Heartstopper Aura deal percentage-based damage, ignoring Bristleback's high health.
* Heartstopper Aura's HP removal does not trigger Bristleback's passive.