Keeper of the Light
* Heroes with silences: 
Puck, 
Doom, 
Riki.
Bristleback
* 
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 his upgraded level 25 talent, it also breaks Bristleback's passive, rendering him more vulnerable.
Additional:
* 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 chooses the Level 25 talent {ValueColor:1|Doom applies Break|25tal} {Symbol:Talent}, he can disable 
Bristleback and Warpath, taking away much of his durability and damage potential in team fights.
Keeper of the Light
* 
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.
Bristleback
* 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.
Keeper of the Light
* Heroes with abilities that blind or cause Legion Commander to miss will prevent her from winning Duels: 
Arc Warden, 
Keeper of the Light, Riki, 
Tinker
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.
* By the same token once Keeper of the Light gets a 
Octarine Core, he can spam Charka Magic to keep his own mana ful
Bristleback
* 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 Bristleback from using abilities in the lane.
* Blink Anti-Mage has very high mobility with this skill, and can easily escape from Bristleback since he has no way to prevent his blink. He can also use this offensively to get in front of Bristleback during fights.
Keeper of the Light
* 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
Keeper of the Light
* 
Finger of Death can instantly shred many targets, especially fragile Heroes like Keeper of the Light, 
Ancient Apparition or 
Bounty Hunter.
Bristleback
* 
Lion's 
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.
Keeper of the Light
* 
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.
Additional:
* 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.
Bristleback
* Outworld Destroyer's high burst damage is not negated by Bristleback's passive. So, even if Bristleback turns his back on Outworld, he 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.
Keeper of the Light
* 
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.
Bristleback
* 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.
Keeper of the Light
* 
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.
Keeper of the Light
* Pugna easily copes on the line with the Keeper of the Light push with his 
Nether Blast, and in addition to 
Nether Ward, the Keeper of the Light is not able to throw Illuminate on creeps for a long time, so Pugna earns more gold and a level on the line
Additional:
* Pugna easily copes on the line with the Keeper of the Light push with his Nether Blast, and in addition to Nether Ward, the Keeper of the Light is not able to throw Illuminate on creeps for a long time, so Pugna earns more gold and a level on the line
Bristleback
* 
Guardian Sprint allows Slardar to outrun Bristleback, even when slowed by Viscous Nasal Goo.
* 
Corrosive Haze's armor reduction makes Bristleback much less tanky.
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.
* 
Storm Surge allows Razor to outdistance Bristleback, even with a few stacks of Viscous Nasal Goo on him. Also, if Razor has his Shard, it will deal full damage to Bristleback every time he uses Viscous Nasal Goo (as Bristleback will face him to cast it).
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.
Bristleback
* 
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.
Keeper of the Light
* Heroes with dispels: 
Legion Commander, 
Oracle, 
Slark, 
Phantom Lancer
Bristleback
* 
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 lost 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 the Viscous Nasal Goo debuff on Slark.
* Although Dark Pact cannot dispel Quill Spray, meaning that Slark will still receive quill stack damage even if he used 
Shadow Dance before.
* Slark builds 
Silver Edge in almost every game, an item that greatly counters Bristleback.
Keeper of the Light
* Melee carries during the laning phase: 
Sven, Slark
Bristleback
* 
Shukuchi gets Weaver in front of Bristleback, negating the protection from Bristleback.
* Weaver's mana break talent depletes Bristleback's mana pool, preventing him from spamming abilities.
Bristleback
* 
Whirling Death deals damage while also reducing {Show:A|Timbersaw|Whirling Death|value4} of Bristleback's strength, making him less tanky.
* 
Reactive Armor can sustain through multiple Viscous Nasal Goo and Quill Spray stacks.
* 
Timber Chain makes it hard for Bristleback to slow down Timbersaw even with Viscous Nasal Goo.
Bristleback
* 
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.
Bristleback
* Heroes with high health especially Strength heroes will take more damage on Sun Ray: 
Axe, 
Pudge, 
Bristleback, 
Mars.
Bristleback
* 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.
Keeper of the Light
* Heroes with hastes: 
Dark Seer, 
Lycan
Bristleback
* 
Shadow Demon's 
Demonic Purge with Aghanim's Scepter disables Bristleback's passives.
Keeper of the Light
* Heroes with teleports to escape Solar Blind and Will-O-Wisp: 
Phantom Assassin, Puck, 
Queen of Pain, 
Storm Spirit
Keeper of the Light
* 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.
Keeper of the Light
* Heroes with channeling abilities: 
Enigma, 
Witch Doctor, 
Crystal Maiden.
Keeper of the Light
* Heroes with teleports to escape Solar Blind and Will-O-Wisp: Phantom Assassin, Puck, Queen of Pain, Storm Spirit
Keeper of the Light
* 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.
Bristleback
* While Jakiro's damage is going to be little more then average against him due to his Bristleback. His large quantity of stuns can prevent Bristleback from getting his much needed Warpath stacks, while also giving his allies a chance to counter his high defense.
* Dual Breath and Liquid Frost both reduce Movement Speed, removing one of Bristlebacks greatest strengths.
* Liquid Fire reduces Bristlebacks Attack Speed, making it harder for him to burst down a hero with Warpath.
* However Bristleback can generally catch and kill a lone Jakiro. And Jakiro is only effective in a group.
Bristleback
* 
Macropyre's frequent damage ticks causes Bristleback to activate repeatedly, resulting in free damage as long as Bristleback faces away from Jakiro.
Keeper of the Light
* 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...
Keeper of the Light
* Heroes that can jump and kill him: 
Meepo, 
Clinkz, Templar Assassin
Bristleback
* 
Batrider's turn rate slow from 
Sticky Napalm makes it harder for Bristleback to keep his back towards the enemy.
Keeper of the Light
* 
Rage allows him to be immune to all of Ezalor's abilities. Also, the increased movement speed combined with the slow from 
Ghoul Frenzy and the squishy nature of Ezalor allows Lifestealer to take him down very quickly.
Bristleback
* Heroes with high physical damage can damage Lifestealer more than he can heal: Bristleback, Clinkz, Luna,
Shadow Fiend, 
Slardar, Terrorblade
Keeper of the Light
* 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.
Keeper of the Light
* Keeper of the Light's Blinding Light makes Juggernaut miss his attacks. However, it can be dispelled easily with Blade Fury.
Bristleback
* 
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.
Additional:
* 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.
Bristleback
* Enemies that possess high defenses through magic resistance, damage reduction, or high regeneration will make it difficult to whittle their health down to get to Reaper's Scythe's threshold. Such heroes include Bristleback (although only from behind), 
Spectre, 
Ursa, and Dragon Knight.
Bristleback
* 
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.
Additional:
* 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.
Keeper of the Light
* Any hero that can nullify effects of Chronosphere: (Keeper of the Light with Aghanim's Scepter during daytime, 
Winter Wyvern), banishing him or Faceless Void (
Outworld Destroyer, Shadow Demon, 
Earth Spirit with Aghanim's Scepter) or protecting him in other ways (
Dazzle, Oracle, 
Abaddon) can greatly limit Chronosphere's potential.
Keeper of the Light
* Illuminate wipes out Broodmother's spiders and prevents her from pushing the lane. It also gives vision to reveal where broodmother is hiding in the trees.
Bristleback
* Quill Spray destroys spiderlings, and hits Broodmother even when she's regenerating in her webs. This makes Bristleback one of her hardest counters in lane.
Additional:
* Bristleback reduces most of Broodmother's and her spiderlings' damage.
* Quill Spray will hit any spiders in its proximity, hindering Broodmother's fighting and farming capabilities.
Keeper of the Light
* Heroes with channeling abilities: Enigma, Witch Doctor, Crystal Maiden.
Keeper of the Light
* Illuminate can wipe the pushing Eidolons in a lane with ease, diminishing Enigma's laning presence by a lot.
* 
Solar Bind will severely slow down Enigma and make him more vulnerable to magical damage more he moves for it's duration.
* However, Keeper of the Light does not have any way to cancel 
Black Hole outside from Will-O-Wisp provided by Aghanim's Scepter.
Bristleback
* Bristleback's constant harass from Quill Spray will greatly hurt Enigma's laning and kill his Eidolons.
* However, Bristleback has no way of canceling Black Hole at all. And Bristleback is not a hero that goes for disabling items to counter that problem.
Keeper of the Light
* 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
Bristleback
* Heroes that have AoE damage: 
Lina, Keeper of the Light, Timbersaw, 
Leshrac, Bristleback, Axe.
Keeper of the Light
* Heroes with extremely slow movement speed will cripple against Solar Bind: 
Medusa, 
Viper
Additional:
* Will-O-Wisp will keep Medusa busy after she got hit by Blinding Light.
Bristleback
* Other heroes who has armor and slow debuffs won't allow Medusa to disengage from combat: 
Tidehunter, Bristleback, Slardar.
Bristleback
* Combo Quill Spray and items 
Blade Mail can easily trigger from Focus Fire damage.
Additional:
* Using Focus Fire on Bristleback tends to fare badly for Windranger, as he can trigger passive Quill Sprays many times, especially when she attacks him from behind. In addition, Windrun does not protect her from both Viscous Nasal Goo and Quill Spray, rendering her helpless.
* Bristleback's natural tankiness makes it hard for Windranger to effectively burst her down throughout the game.
* Bristleback tends to continuously spam Viscous Nasal Goo to slow down Windranger when she uses Windrun to escape, potentially allowing him to outrun her with his Warpath stacks.
* Bristleback can build 
Lotus Orb to reflect Shackleshot and Focus Fire back at Windranger.
Keeper of the Light
* Blinding Light can knock Monkey King outside of his ultimate, Wukong's Command and can blind him.
* Will-O-Wisp will stun Monkey King from Tree Dance by destroying his tree.
Additional:
* Blinding Light can easily push Monkey King out of Wukong's Command, as well as blinding him.
* Monkey King is vulnerable to burst damage, Solar Bind makes him more so
* However, Keeper of the Light can be easily ganked by Monkey King during early-mid game stage.
Bristleback
* Quill Spray quickly destroys Chaos Knight's 
Phantasms.
Keeper of the Light
* Illuminate clears Beastmaster's summons and is effective against his push.
Bristleback
* Bristleback's abilities are nearly useless for Rubick to 
Spell Steal, as he does not gain the bonuses from Warpath.
Additional:
* Rubick deals little damage on his own, and Bristleback can simply shrug off all his spells and chase Rubick down with his Quill Spray and the damage bonus from Warpath.
* Rubick does not tend to charge forward in teamfights, stay in the front lines under most circumstances, yet effective casts of Quill Spray and Viscous Nasal Goo requires the opposite as they require multiple casts and close range to add up stacks.
* Rubick does not benefit from Warpath through casting the stolen spell.
Bristleback
* Viscous Nasal Goo slows down Dragon Knight and lowers armor, locking him down and making him more vulnerable.
Bristleback
* Bristleback is one of the hardest heroes to gank with a 
Meat Hook and 
Dismember combo, and attempts to do so sometimes backfire on Pudge.
Additional:
* Pudge is particularly susceptible to Bristleback's Viscous Nasal Goo and Quill Spray due to his naturally low armor and poor agility gain.
* Bristleback, in combination with his strength gain, high health, common itemization for magic resistance and damage reduction from Bristleback makes him a poor target for Pudge.
Bristleback
* Quill Spray's constant AoE damage will hit Dark Willow even in Shadow Realm. Its automatic damage will hurt her if she tries to get close and use Bedlam.
Bristleback
* Quill Spray will hit Sand King inside 
Sand Storm, damaging him and putting Sand King's 
Blink Dagger on cooldown, preventing him from escaping.
* 
Epicenter's numerous damage ticks will trigger Bristleback's passive repeatedly during teamfights.
Bristleback
* Arc Warden has relatively lower armor and mobility, which makes him an easy target to apply Quill Spray and Viscous Nasal Goo stacks.
* Arc Warden also does not like to build a Silver Edge as it takes a long time to build up and may slow down the timings for other important items needed in the game like 
Gleipnir.
* However, do note that in a game where Arc Warden's team has many jumping capabilities or good passives, like a Tidehunter or Spectre, a Silver Edge becomes incredibly valuable on Arc Warden as not only can he run away from the jumps, he effectively gets 2 breaks, and Bristleback may not be the best pick.
Bristleback
* 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.
Keeper of the Light
* Heroes with hastes: Dark Seer, Lycan
Keeper of the Light
* Keeper of the Light has a blind, which causes Lycan to miss his attacks.
Bristleback
* Lycan's wolves deal little damage to Bristleback, and are easily killed by Quill Spray, even when they're invisible.
* Lycan's lack of burst damage makes it very hard for him to kill Bristleback, especially when his back is turned.
Additional:
* Quill Spray can be used to kill Lycan's summons.
* Bristleback allows him to stay alive against Lycan while dishing out counter attacks
* He can overpower Lycan with his Warpath instead.
Bristleback
* Lone Druid and The Spirit Bear cannot burst down Bristleback due to Bristleback
* Bristleback can easily run to Lone Druid without any hesitation, with Viscous Nasal Goo to reduce armor and slow the Spirit Bear or Lone Druid and Quill Spray can deal damage to both Lone Druid and the Spirit Bear at the same time
Keeper of the Light
* Heroes with summons/illusions/neutral creep armies: 
Beastmaster, 
Chen, Naga Siren
Keeper of the Light
* Melee carries during the laning phase: Sven, Slark
Keeper of the Light
* 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
Keeper of the Light
* Certain heroes can mess up with Pangolier's positioning and timing (especially if he intends to use Rolling Thunder during combat): 
Vengeful Spirit, Keeper of the Light, 
Huskar, Dark Seer
Keeper of the Light
* Any hero who can counter-initiate in anticipation without getting caught in Reverse Polarity: Sven, 
Omniknight, Enigma, Luna, Naga Siren, Mars, 
Jakiro, 
Venomancer, 
Elder Titan, 
Faceless Void, 
Rubick, Keeper of the Light, 
Pugna, 
Invoker, Spectre, 
Alchemist, 
Treant Protector, Lina, Oracle, 
Zeus, 
Shadow Shaman, 
Phoenix, 
Razor, Huskar, Batrider, 
Kunkka, Tidehunter, 
Wraith King, 
Sand King, Medusa, 
Dawnbreaker.
Bristleback
* Heroes with damage-over-time abilities easily allow Bristleback to turn his back in order to proc Bristleback continuously and to massively reduce to damage dealt to him: Arc Warden, Venomancer, Luna.
Additional:
* Quill Spray and Bristleback harass Luna more efficiently than she does with Lucent Beam.
* Bristleback helps return a lot of damage to Luna’s team if she uses her nukes on him and he has his back to her, and her only way to counter this is by buying Silver Edge.
* Viscous Nasal Goo and Warpath are enough to outrun a speedy Luna.
* Bristleback tends to be a frequent carrier of 
Crimson Guard and 
Eternal Shroud, which are good protection from 
Moon Glaives and 
Eclipse.
* For the same reasons, Bristleback makes a very powerful ally for Luna when they are in the same team.
Keeper of the Light
* Heroes with silences: Puck, Doom, Riki.
Keeper of the Light
* Heroes who are strong against mobile heroes: 
Disruptor, 
Bloodseeker, Kunkka, Keeper of the Light.
Bristleback
* Axe, Bristleback, 
Centaur Warrunner, 
Spirit Breaker, Pudge, Huskar, Wraith King, Doom: These heroes are too tanky for Puck to burst down. Also, all of them have spells which can deal with and shut Puck down reliably.
Bristleback
* Heroes with damage-over-time abilities easily allow Bristleback to turn his back in order to proc Bristleback continuously and to massively reduce to damage dealt to him: Arc Warden, Venomancer, Luna.
Bristleback
* Spirit Breaker's 
Nether Strike with 
Aghanim's Shard disables Bristleback's passives.
Keeper of the Light
* Heroes that punish mobile heroes: Bloodseeker, Keeper of the Light, Kunkka, Disruptor.
Bristleback
* Heroes who can continue dealing damage even while being stunned: Luna, Razor, Axe, Bristleback, Leshrac, 
Death Prophet, Jakiro.
Keeper of the Light
* Heroes which rely exclusively on right clicks will struggle somewhat against Blinding Light: Phantom Assassin, Wraith King, Medusa
Bristleback
* Bristleback's Viscous Nasal Goo can catch and slow Bounty Hunter. Warpath and Quill Spray can defeat him quickly due to his small HP pool when compared to Bristleback's.
Keeper of the Light
* Heroes with dispels: Legion Commander, Oracle, Slark, Phantom Lancer
Bristleback
* Bristleback's tankiness and damage reduction from the rear makes him very hard for Phantom Lancer to chase and finish off, due to his lack of burst damage.
* Quill Spray quickly destroys Phantom Lancer's illusions.
* Bristleback's passive costs no mana, meaning that it will continue to trigger even if Phantom Lancer drains Bristleback's mana with 
Diffusal Blade.
Additional:
* Bristleback's tankiness and damage reduction from the rear makes him very hard for Phantom Lancer to chase and finish off, due to his lack of burst damage.
* Quill Spray destroys Phantom Lancer's illusions.
* Bristleback's passive costs no mana, meaning that it will continue to trigger even if Phantom Lancer drains Bristleback's mana with Diffusal Blade.
Keeper of the Light
* Squishy heroes, usually supports, like Lion, Ancient Apparition, Keeper of the Light etc can die quickly to Tiny's magic burst.
Bristleback
* Tiny's nonexistent armor in the early game makes him very vulnerable to Quill Spray's large amounts of physical damage.
* Bristleback decreases Tiny's high burst damage against Bristleback.
* Viscous Nasal Goo can slow Tiny to a crawl and allows Bristleback to easily kite him with his high movement speed and Quill Spray's long range, as Tiny has no ability to escape.
Keeper of the Light
* Heroes with channeling abilities: Enigma, Witch Doctor, Crystal Maiden.
Bristleback
* Viscous Nasal Goo can hinder Crystal Maiden's already abysmal mobility, which allows Bristleback (or his teammates) to run her down and kill her.
* Bristleback frequently builds Blade Mail, which can quickly kill Crystal Maiden if her ultimate is used while he is under its effect.
* The passive part of Bristleback will trigger many, many times under the damage from Freezing Field, and as the stacks increase, the damage output from each successive cast (or proc) will eat away at Crystal Maiden's small HP pool.
Keeper of the Light
* Heroes with silences: Puck, Doom, Riki.
Bristleback
* Quill Spray will hit Riki even when he is invisible.
* 
Cloak and Dagger's bonus backstab damage is rendered irrelevant against Bristleback.
* 
Smoke Screen does not stop Bristleback's passive from activating.
* Due to Bristleback's natural tankiness, he is an ideal 
Gem of True Sight carrier, directly countering Riki's invisibility.
Additional:
* The bonus Backstab damage from Cloak and Dagger is rendered irrelevant with Bristleback and hurts Riki more than him because of the passive Quill Spray.
* Riki can still get damaged by Bristleback's Quill Spray while invisible, and it can be hard to deal with in lane.
* Bristleback is not too bothered by Smoke Screen. Though he cannot use Quill Spray manually inside it, it still procs passively when he takes damage from the back. The movement speed from Warpath allows him to get out of the area easily.
* Due to Bristleback's natural tankiness, he is an ideal Gem of True Sight carrier.
* Riki rarely buys Silver Edge to break Bristleback's passive because the invisibility aspect of it is redundant.
Keeper of the Light
* Vulnerable spellcasters with no escape mechanisms are easy targets for Huskar: 
Lich, Crystal Maiden, 
Silencer, Keeper of the Light, Venomancer, etc.
Bristleback
* The damage from 
Burning Spear can be reduced by turning away from Huskar.
* Bristleback can bait Huskar into using 
Life Break on him, then turn around and receive very little damage.
Additional:
* Bristleback's tankiness and Bristleback allow him to outlast Burning Spears' damage-over-time at almost any point in the game. In addition, if Huskar chooses to cast Life Break on Bristleback, Bristleback can simply turn around before it hits and receive little damage.
* Viscous Nasal Goo will reduce Huskar's low armor even further, and Quill Spray and Warpath will tear him down extremely quickly.
Keeper of the Light
* Heroes that can jump and kill him: Meepo, Clinkz, Templar Assassin
Bristleback
* Quill Spray usually hits Meepo's clones, although Bristleback cannot turn his back when rooted with 
Earthbind.
Keeper of the Light
* Heroes with dispels: Legion Commander, Oracle, Slark, Phantom Lancer
Bristleback
* Fortune's End cannot dispel Warpath stacks on Bristleback or Quill Spray stacks on allies.
* Bristleback can heavily reduce Oracle's damage output. With it, Oracle may accidentally heal Bristleback with Purifying Flames, especially if Bristleback has bonus magic resistance.
Bristleback
* Terrorblade's 
Sunder is not affected by the Bristleback damage reduction.
Keeper of the Light
* 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
Keeper of the Light
* Heroes with teleports to escape Solar Blind and Will-O-Wisp: Phantom Assassin, Puck, Queen of Pain, Storm Spirit
Keeper of the Light
* Heroes which rely exclusively on right clicks will struggle somewhat against Blinding Light: Phantom Assassin, Wraith King, Medusa
Bristleback
* 
Nethertoxin disables Bristleback's passive.
* 
Viper Strike and 
Poison Attack slow down Bristleback's movement speed, making him unable to get out from Nethertoxin.
Additional:
* Viper Strike can disable 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.
Keeper of the Light
* The Keeper of the Light easily farms on the line against the Viper, due to the fact that it has a long-range Illuminate, and the Viper, in turn, cannot use its advantage of dominance on the center line, due to the fact that it does not reach the Keeper of the Light
Additional:
* The Keeper of the Light easily farms on the line against the Viper, due to the fact that it has a long-range Illuminate, and the Viper, in turn, cannot use its advantage of dominance on the center line, due to the fact that it does not reach the Keeper of the Light
Bristleback
* Axe forces Bristleback to turn around with 
Berserker's Call, allowing allies to attack him without fear of his passive.
Bristleback
* Heroes who can stop Axe from getting close will severely inhibit his presence in fights: Bristleback, Crystal Maiden, Batrider, Arc Warden, Winter Wyvern, 
Clockwerk
Keeper of the Light
* 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.
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*
* 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
*
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.
Viscous Nasal Goo or 
Quill Spray while silenced, effectively blocking a major part of the hero's damage and preventing 
Warpath charges from stacking.
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*
Additional:
* Bristleback will not be able to cast
* 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.