* Decrepify turns the target ethereal, protecting them from Chaos Knight's and his illusions' attacks.
* Life Drain instantly destroys illusions. It can effectively negate Phantasm when upgraded with Aghanim's Scepter.
* Nether Blast quickly clears out illusions and can harass Chaos Knight in lane.

* Quill Spray quickly destroys Chaos Knight's Phantasms.

* Enigma's abilities have a huge mana cost, meaning that Nether Ward will deal a lot of damage to Enigma.
* Channeling Black Hole will render Enigma immobile, making him easy target for all of Pugna's abilities, especially Nether Blast, and Life Drain.

* Bristleback's tankiness can enable him to chase Enigma out of a teamfight, making it difficult to initiate with a Black Hole.

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

* Nether Ward will cause an unfriendly area for Medusa, draining her mana.

* Pugna: Decrepify prevent the Spirit bear from attacking or protect allies from it.

* 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

* Heroes who are reliant on physical damage will be nullified by Decrepify: Riki, Wraith King, Juggernaut.

* 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 still gets 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.
Additional:
* 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.

* 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.

* Pugna's Decrepify prevents the target from taking physical damage or doing damage, which poses a huge problem for Lycan, as he mainly deals physical damage.

* Any hero that can outrange Plague Ward can neutralize them without putting themselves at risk of receiving Poison Sting: Arc Warden, Chen, Clinkz, Drow Ranger, Lina, Mirana, Nature's Prophet, Pugna and Sniper.
* Special mention to heroes has attack range talent can also outrange Plague Ward.

* 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

* Pugna can save allies with both healing or by making them ethereal.

* Bristleback decreases Tiny's high burst damage against Bristleback.
* Tiny's high damage will also proc Bristleback multiple times.
* Viscous Nasal Goo can help counteract the bonus armor granted by Grow.

* Amazingly, Enchantress has even lower health than Pugna. Though she does pack quite a punch through Impetus, she can't use it if she is under Decrepify.
* Pugna's Magical DPS is way greater than the heal from Nature's Attendants, which will also harm her quite a bit if she's next to Nether Ward.

* 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, so Bristleback can simply shrug off all his spells and chase you down with his spells and attacks.
* Quill Spray requires multiple casts and close range to add up stacks. Because Rubick does not stay in the front lines, it's generally not a good spell for him to steal.
* Viscous Nasal Goo will slow Rubick down even further and reduce his armor, making him vulnerable to Quill Spray and the damage bonus from Warpath.

* Decrepify prevents Shadow Fiend from attacking for its duration, potentially preventing him from getting a kill.
* Nether Ward can do heavy damage to Shadow Fiend if he tries to cast his Requiem of Souls or spam Shadowraze.
Additional:
* Decrepify prevents Shadow Fiend from attacking for its duration, potentially preventing him from getting a kill.
* Nether Ward can do heavy damage to Shadow Fiend if he tries to cast his Requiem of Souls and his Shadowraze.

* Even though Pugna's low HP means that he can be quickly burst down, his Nether Ward heavily punishes casters whose spells cost a lot of mana, like Zeus. Casting 4 of his active spells, including Nimbus, close to an enhanced level 4 Nether Ward, can make the ward deal up to 1750 magical damage.
* Decrepify can further increase the damage dealt by Nether Ward upon Zeus. However, if used on Pugna himself or on one of his allies, it will amplify the damage done by Zeus' abilities.

* Nether Blast is one of the best tower pushing abilities in the game, with a low cooldown. A competent Pugna will (at the very least) destroy tier 2 towers and make space for his team before Spectre can finally come online.
* Spectre's spells, while not spammable, have a fairly high mana cost, so Nether Ward can be fairly damaging to Spectre early game. The mana degen will also dampen Spectre's early game power significantly.
* Once Pugna gets Aghanim's Scepter, he can spam Life Drain on any illusion Spectre summons, whether it'd be from Haunt, Manta Style, or some other means.
* In addition, Pugna can disable Spectre's Desolate ability (although its damage is pure, it requires physical attacks) with his Decrepify ability, leaving Spectre only with Spectral Dagger.

* Decrepify can be used on allies to prevent them from attacking Axe and triggering Counter Helix during Berserker's Call. He can also cast it on Axe to prevent anyone from attacking him.
* Life Drain can be used to heal himself or allies caught in Berserker's Call, preventing them from dropping low enough for Axe to kill them with Culling Blade.

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

* Nether Blast, Decrepify and Life Drain deal high magical damage and bypasses Bulwark.
* Nether Ward reduces the amount of abilities Mars can use during fights and forces Mars to be careful about the heavy mana cost of Arena Of Blood.
* Pugna is one of few heroes that can contest Mars' ability to push and defend towers early on.

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

* Cold Embrace is a death sentence against Pugna, since its the perfect setup for all his abilities, especially Life Drain.
* Decrepify can be cast to save the ally under Winter's Curse effect, wasting most of its duration.
* Winter Wyvern's abilities require a lot of mana, allowing Nether Ward to deal lots of damage.

* Nether Ward can do a ton of damage to Disruptor because of his high mana costs.
* Life Drain can be used to heal an ally trapped by Static Storm-Kinetic Field combo (if Pugna is not a target).

* 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.

* Nether Ward will make Skywrath Mage next to useless in fights, as his low hp pool will not allow him to sustain through the damage of the ward should he choose to cast spells. Be wary though that Skywrath's huge burst will make very quick work of Pugna's low hp should the ward be destroyed, and Decrepify won't help you at all.
Additional:
* Due to the high mana cost of his spells and the low cool down of them, Nether Ward can seriously damage Skywrath Mage if he isn't careful.
* Skywrath Mage's fragility makes him very susceptible to Pugna's high burst damage.

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

* Pugna's Decrepify can render Templar Assassin's physical attacks useless.
* Pugna can also cast Life Drain on Templar Assassin, burning her Refraction instances.
* On the other hand, Pugna generally has low health and armor. Use this to your advantage.

* Leshrac needs to be close to target in order to do damage, Pugna can outrun Leshrac with ease due to his superior movement speed.
* Split Earth can also be hard to land on Pugna for the same reason.
* Leshrac uses huge amounts of mana to do damage, Nether Ward forces him to either not contribute in a fight or kill himself in the process.
Additional:
* Nether Ward punishes Leshrac's constant mana usage from spamming spells.
* Leshrac needs to be in the thick of the fight to deal damage, and so cannot escape from Nether Blast nor Life Drain easily.

* 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.

* Pugna's Nether Ward damages Sand King when he channels Epicenter, preventing him from using Blink Dagger afterward.

* 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.

* Troll Warlord can't switch targets at will, in order to build Fervor stacks, which makes it easy to use Decrepify in order to save allies
* During Battle Trance, Pugna can easily use Nether Blast, Decrepify and Life Drain on him

* 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'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.
Additional:
* 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.

* Decrepify prevents Omnislash damage, until Juggernaut gets a Nullifier.
* Without a disable, Pugna's high movement speed makes it harder to chase him with Blade Fury.
* Juggernaut has low mana and his skills cost large amount of mana. Nether Ward will hurt him more and even worse, the damage from the ward is inflicted before the spell immunity provided by Blade Fury.
Additional:
* Decrepify is the perfect tool against Omnislash until he gets a Nullifier, and even then he will probably waste a couple of slashes before he uses it.
* Without an extra disable, Pugna's high movement speed makes it impossible to chase him with Blade Fury.
* Unlike some other carries like Slark or Phantom Assassin, Juggernaut's spells cost a hefty amount of mana and he will seriously get hurt by Nether Ward. Don't forget the damage from the ward is inflicted before the spell immunity is provided by Blade Fury.

* 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.

* Bristleback need not worry about charging into Magnetic Field, and quickly clearing up Arc Warden's summons and Tempest Double with Quill Spray.
Additional:
* Bristleback activates frequently while he escapes from Arc Warden's Necronomicon army.
* Arc Warden has little armor and mobility, which makes him an easy target to apply Quill Spray and Viscous Nasal Goo stacks.

* Nether Ward discourages Tinker from using abilities and items due to its high damage against heavy mana usage.

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

* 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.

* 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 high movement speeds like Pugna and Meepo can run around, to, or away from Snapfire during Mortimer Kisses and dodge the projectiles easily due to their slow speed.
* Heroes with mobility spells (such as Queen of Pain's Blink and Clockwerk with Hookshot) can easily avoid Lil' Shredder and Mortimer Kisses.
* Heroes with high movement speeds like Pugna and Meepo can run around, to, or away from Snapfire during Mortimer Kisses and dodge the projectiles easily due to their slow speed.

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

* Heroes who are reliant on physical damage will be nullified by Decrepify: Riki, Wraith King, Juggernaut.

* 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.
Additional:
* Quill Spray cleans up Phantom Lancer's illusions in no time.
* Phantom Lancer's complete lack of burst damage makes it nearly impossible for him to kill Bristleback during chases.

* Since Life drain takes out illusions instantly, Pugna with a scepter is decent versus plenty of illusion heroes, most notably Naga Siren and Terrorblade and the aforementioned Chaos Knight. Phantom Lancer is an exception.

* 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 damage burst can often kill Chen or his allies before he can use Hand of God: Lina, Techies, Shadow Fiend, Pugna, Nyx Assassin.

* Heroes that can punish aggressive heroes, such as: Leshrac, Shadow Demon, Pugna, Death Prophet.

* Pugna's Decrepify makes sure that either Alchemist is unable to hit anyone while also being slowed and susceptible to magical damage, or can protect an ally from physical attacks. Besides, Pugna can push early on, when Alchemist is not strong enough to repel it, so by the time Alchemist comes online, he might be forced to sit in base.

* Since Life drain takes out illusions instantly, Pugna with a scepter is decent versus plenty of illusion heroes, most notably Naga Siren and Terrorblade and the aforementioned Chaos Knight. Phantom Lancer is an exception.

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

* 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 & 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.

* All of Pugna's abilities are active, making Demonic Purge break from Aghanim's Scepter useless.
* Nether Ward punishes Shadow Demon's constant mana usage from spamming spells, especially Shadow Poison.
* An attempt to save an ally using Disruption can easily become a perfect setup for a Nether Blast for the enemy.
* Life Drain can be used to heal Pugna or an ally to save them from Shadow Demon's abilities.
* However, it can be cancelled by Disruption until Pugna buys defensive items.

* Decrepify prevents Faceless Void from attacking trapped allies inside Chronosphere, wasting a large portion of its duration if Faceless Void can't dispel it.

* Nether Ward will be problematic for heavy nukers and spammers like Skywrath Mage, Lina, Lion and Invoker, but don't use Decrepify defensively against them as you'll be helping them out more than anything.

* Since Life drain takes out illusions instantly, Pugna with a scepter is decent versus plenty of illusion heroes, most notably Naga Siren and Terrorblade and the aforementioned Chaos Knight. Phantom Lancer is an exception.

* Decrepify on either hero stops Legion Commander from completing a Duel, and dissuades her from initiating Duels on ethereal allies.
* Life Drain can help Pugna's teammates win a fight, either by killing Legion Commander or replenishing her target's health.
Additional:
* Decrepify prevents Legion Commander from attacking allies during Duel, regardless if it's used on her or on the ally .
* Pugna can easily cast Decrepify, Nether Blast and Life Drain on Legion during the 4/4.75/5.5/8 seconds of duel

* Pugna's Decrepify allows him to save allies from being ganked by Viper, since Viper mostly relies on direct attacks in order to deal damage.
* Nether Ward can discourage Viper from spamming his abilities.
* Viper's damage over time is not enough to kill Pugna as he will have more than enough time to save himself (or his allies) with Life Drain and Viper has no solutions to cancel it.
* Pugna has no passive abilities, which renders Nethertoxin nearly useless.

* Nether Ward can punish Timbersaw, as Timbersaw is a spell-caster with low cooldowns. Furthermore, Timbersaw usually appears in the midst of battle, placing himself in range of Nether Ward's Mana Flares.
* Timbersaw has no stuns or silences to stop Life Drain. Since all of Pugna's Spells are magical, the damage can be devastating to Timbersaw, especially when combined with Decrepify
Additional:
* Nether Ward can punish Timbersaw, as Timbersaw is a spell-caster with low cooldowns. Furthermore, Timbersaw usually appears in the midst of battle, placing himself in range of Nether Ward's Mana Flares.
* Timbersaw has no stuns or silences to stop Life Drain. Since all of Pugna's Spells are magical, the damage can be devastating to Timbersaw.
* Decrepify can further increase all the magical damage done to Timbersaw, bypassing the enhanced physical resistance he can get from Reactive Armor.

* Because Invoker relies on casting a large amount of spells to contribute to fights, Nether Ward can force him to not cast anything at all or take a large amount of damage to cast spells.

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

* 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.

* Quill Spray and Bristleback harass Luna more efficiently than she does with Lucent Beam.
* Bristleback withstands Luna’s nukes, and gives lots of damage in return.
* 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.
Additional:
* Multiple instances of damage from Eclipse will trigger Bristleback's passive repeatedly in a short time, dealing tremendous damage to Luna and her teammates.
* Luna's damage burst may be high, but it will not be enough for her to take down Bristleback.

* For the better part of the game, he will take more damage from your ward than he deals to you with Arcane Orb.
* It will take a huge difference in farm or itemization between you for him to deal any damage to you with Sanity's Eclipse, provided he doesn't die first from casting it next to your ward.
* Decrepify allows Pugna to be immune to the attacks from Arcane Orb.

* 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.