* 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.

* While Broodmother can hide in the trees with Spin Web, Primal Beast's ability to trample trees down can give him an edge in catching her.
* Insatiable Hunger will not do much vs Primal Beast's onslaught of disables.
* While Silken Bola can slow Primal Beast down, it's not enough to stop Trample from doing more damage than Broodmother can do back.
* Spawn Spiderlings will be destroyed by Onslaught and Trample very easily.

* Quill Spray quickly destroys Chaos Knight's Phantasms.

* Illusion heroes will struggle against Primal Beast's area damage capability, such as Chaos Knight, Naga Siren, Terrorblade.

* 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.

* Any hero with low mobility and max healthsuch as Silencer, Crystal Maiden etc.

* Multiple instances of damage from Eclipse will trigger Bristleback's passive repeatedly in a short time, dealing tremendous damage to Luna and her teammates.
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.
* Viscous Nasal Goo and Warpath are enough to outrun a speedy Luna.
* Bristleback tends to be a frequent carrier of Crimson Guard, which is good protection from bouncing glaives.

* 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...

* Other heroes who has armor and slow debuffs won't allow Medusa to disengage from combat: Tidehunter, Bristleback, Slardar.

* Hard carries who just want to farm and be left alone will not appreciate Primal Beast, heroes such as Medusa, Drow Ranger...

* Heroes that have AoE damage: Lina, Keeper of the Light, Timbersaw, Leshrac, Bristleback, Axe

* Heroes with unorthodox escapes will struggle against Primal Beast, such as Nature's Prophet, Tinker, and Templar Assassin.

* Morphling relies on Attribute Shift (Agility Gain) to take last-hits. Primal Beast's burst damage ability can constantly threaten Morphling, especially due to his short attack range. If forced to escape with Waveform, Primal Beast can catch up with Onslaught.

* Primal Beast is one of Sniper's greatest counters, as he has no real means of escape and is very squishy, especially in the early game. Sniper's potshots and Shrapnel can contribute to Primal Beast's Uproar and further make him tankier than he already is. Onslaught allows him to close the gap on Sniper at his own volition, and Trample can deal serious damage to his meager health pool. Should Sniper acquire an item of escape, Primal Beast can still delay him with Pulverize. Overall, Sniper is an ideal target for Primal Beast to constantly threaten in all stages of the game, and it can force Sniper to itemise for him.

* Viscous Nasal Goo slows down Dragon Knight and lowers armor, locking him down and making him more vulnerable.

* Phantom Assassin is known to be weak against bursts of magical damage, something Primal Beast excels at from the beginning of the game. He can use this to his advantage by constantly hunting Phantom Assassin down, especially if she is left alone to farm.
* Primal Beast is a good carrier of Ethereal Blade, Vanguard and Shiva's Guard all of which are very good against Coup de Grace and Phantom Strike.
* Even though Primal Beast does alot of physical damage early on, later once Blur becomes more potent, she may find herself being overwhelmed by Trample and Pulverize instead.
* Primal Beast also has a level 25 talent which makes Pulverize go through spell immunity which is especially effective against a hero like Phantom Assassin who relies on it.

* 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.

* Trample and Pulverize can be used to cancel Life Drain very quickly.
* Pugna has a very low strength gain and as a support does not have much gold to buy health items, making him vulnerable to Primal Beast's onslaught of magical damage.
* Ironically, Decrepify actually just increases Primal Beast's damage on the targeted ally if Trample is activated. However, it can be used to slow him down and prevent any further Trample damage.

* 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.

* 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.

* 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.

* Primal Beast can use Uproar to tank a portion of Omnislash, giving him an edge in surviving it. Primal Beast can also dash away after Omnislash with Onslaught, disallowing Juggernaut from any follow-ups.
* Blade Fury will never do more damage than Uproar once the stacks are activated.
* Primal Beast is very commonly buying items that are good against Juggernaut, such as Ethereal Blade and Heart of Tarrasque.

* 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.

* Magnus is not tanky and struggles against burst damage, something Primal Beast excels at in the early-to-mid game. Primal Beast is also able to out-damage Magnus's Empower and can even contribute to his Uproar stacks.
* Using Skewer to drag Primal Beast while he is trampling will count as movement and will trigger a rapid number of slams, which could prove lethal to Magnus.

* 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.

* Dispersion reduces damage based on a percentage, which is very minimal against large amounts of small instances of damage such as Trample. It reduces each tick by about 14 at maximum level, which is very small.
* Desolate is never a threat to Primal Beast due to his large health pool and Uproar still out damaging the ability.
* Onslaught can allow Primal Beast to chase Spectre fleeing with Spectral Dagger, as both skills phase through trees and terrain.
* Primal Beast can be strong enough to force a farming Spectre to flee with Haunt, putting it on a long cooldown and potentially leading her to an ally that can finish her off.
* Primal Beast excels at early aggression, pushing weak carries out of lane and farming areas he wants to control. Overall just not a pleasant matchup for Spectre.

* 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.

* 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.

* 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.

* Quill Spray usually hits Meepo's clones, although Bristleback cannot turn his back when rooted with Earthbind.

* 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.

* 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 who cannot escape from Trample early might be easy first blood. Heroes like Witch Doctor and Omniknight should play very cautiously alone...

* Bristleback, Centaur Warrunner, Spirit Breaker, Pudge, Huskar: 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.

* Heroes with high physical damage can damage Lifestealer more than he can heal: Bristleback, Clinkz, Luna,Shadow Fiend, Slardar, Terrorblade

* 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 damage-over-time abilities will not only proc Bristleback's passive continuously, they will also do little harm to him when he is facing away from the source: Venomancer, Arc Warden

* Heroes who have low armor but very high health will be difficult for drow to burst down quickly: Primal Beast, Axe, Centaur Warrunner.

* 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.

* Illusion heroes will struggle against Primal Beast's area damage capability, such as Chaos Knight, Naga Siren, Terrorblade.

* Heroes who cannot escape from Trample early might be easy first blood. Heroes like Witch Doctor and Omniknight should play very cautiously alone...

* Heroes with unorthodox escapes will struggle against Primal Beast, such as Nature's Prophet, Tinker, and Templar Assassin.

* Since Primal Beast is highly mobile with Onslaught alone, he will be difficult to catch with both Cold Feet and Ice Blast.
* Ice Blast is less effective due to Primal Beast's massive health pool and resistance to taking damage.
* While Chilling Touch can be used to slow Primal Beast briefly, it is not enough to beat him back, and can also contribute to his Uproar stacks.

* 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.

* 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

* Illusion heroes will struggle against Primal Beast's area damage capability, such as Chaos Knight, Naga Siren, Terrorblade.

* Heroes who continue dealing damage while being stunned: Luna, Razor, Axe, Bristleback, Leshrac,

* Heroes who can slow and kite Axe will severely inhibit his presence in fights: Bristleback, Crystal Maiden, Batrider, Arc Warden, Winter Wyvern, Clockwerk

* 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.

* Macropyre's frequent damage ticks causes Bristleback to activate repeatedly, resulting in free damage as long as Bristleback faces away from Jakiro.

* Dark Pact, Shadow Dance and Depth Shroud will do nothing against Onslaught and Trample, as they are both ground area-of-effect spells.
* Primal Beast has a gigantic hitbox, which could be difficult for Slark to escape with Pounce should Primal Beast choose to block him. Pounce also does not completely prevent Primal Beast from trampling offensively, as he still has some room to move.
* Primal Beast has a huge health pool; shedding it with Essence Shift can take time and may allow Primal Beast to build Uproar against him. Should he survive Slark's slew of skills, Primal Beast can simply Pulverize him to finish him off.

* 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.

* Onslaught prevents all of Razor's abilities from being effective against him, especially in the laning stage.