* Shadow Demon, Outworld Destroyer and Tusk can all save a Lasso'd teammate with their defensive spells.

* Ensnare disables Templar Assassin's invisibility and Blink Dagger (a core item on Templar Assassin), and her illusions will break Refraction easily.

* Heroes that build Diffusal Blade or can fit it well into their item build will also make Medusa much less tanky: Riki, Naga Siren, Terrorblade, Juggernaut, Spectre, Slark.

* Nyx Assassin's skillset is mostly single-targeted, therefore he will have difficulties against heroes with illusions and summons: Naga Siren, Broodmother, Lycan, Visage, Phantom Lancer. And to make things worse, Nyx Asassin is not a common Battle Fury, Maelstrom, Mjollnir, Gleipnir or Radiance wielder to counter this problem.

* Arcane Orb and Sanity's Eclipse can often kill Chen or his allies before he can save them with Hand of God.
* Arcane Orb, Astral Imprisonment and Sanity's Eclipse can clear waves of Chen's converted creeps.

* Naga Siren can make landing Chen's combo very hard due to her being an illusion hero thanks to Mirror Image.
* Rip Tide can deal big damage to Chen and reduce Chen's armor, as well as easily kill all of Chen's creeps.
* Naga Siren often builds Radiance, which allows her to quickly clear Chen's creeps.
* Ensnare will prevent Chen from escaping.
* With Aghanim's Scepter, Naga Siren can get access to Reel In, which can separate Chen from his creeps and draw him closer to Naga Siren and her team to finish her off. To make things worse, Chen has no way to cancel Reel In on his own, and must rely on outside from {U:Centaur Conqueror} or {U:Mud Golem} under his control.
* Carry or Nuker Naga Siren can often finish off Support Chen before he can have a chance to activate Hand of God.
Additional:
* Naga Siren can make landing Chen's combo very hard due to her being an illusion hero.
* Rip Tide can deal big damage to Chen and reduce Chen's armor, as well as easily kill all of Chen's creeps.
* Naga Siren often builds Radiance, which allows her to quickly clear Chen's creeps.
* Ensnare will prevent Chen from escaping.
* With Aghanim's Scepter, Naga Siren can get access to Reel In, which can separate Chen from his creeps and draw him closer to Naga Siren and her team to finish her off. To make things worse, Chen has no way to cancel Reel In on his own, and must rely on outside from {U:Centaur Conqueror} or {U:Mud Golem} under his control.
* Carry or Nuker Naga Siren can often finish off Support Chen before he can have a chance to activate Hand of God.

* Arcane Orb deals heavy damage to both Lone Druid and the Spirit Bear.
* Astral Imprisonment can prevent the Spirit Bear from attacking, which is Lone Druid's main damage output.
* Sanity's Eclipse deals heavy damage to Lone Druid.

* Unless Lone Druid purchases a Black King Bar for his Spirit Bear, Ensnare will easily kite the Spirit Bear.
* Song of the Siren allows Naga Siren and her team to completely bypass the Spirit Bear and hunt for the Lone Druid himself when starting a fight.
* Lone Druid's lack of innate AoE capabilities mean that Naga Siren's illusions have no problem against him.

* Arcane Orb's pure damage penetrates Guardian Angel's defense.
* Astral Imprisonment's mana steal is devastating to Omniknight's already low mana pool.

* Even though Naga Siren relies on direct attacks to deal damage for most of the time, Song of the Siren allows her to easily waste Guardian Angel.
* Ensnare fully works on targets affected with Heavenly Grace. However, Ensnare is dispellable with any dispel, and so can be dispelled by Heavenly Grace.
* As an agility hero that relies on illusions, Naga Siren is one of the most natural Diffusal Blade carriers, the bane of every hero with a small mana pool. Naga Siren can also buy items that deal magical damage like Radiance, Dagon, Ethereal Blade, Revenant's Brooch, Veil of Discord and Gleipnir to attack Omniknight's allies protected with Guardian Angel.
Additional:
* Although Naga Siren relies mostly on physical damage, Song of the Siren can be used to time out Guardian Angel, giving Naga Siren's team an easy opportunity to counter-initiate.
* Radiance allows it's owner to deal magical damage to multiple enemy heroes at once, and since Naga Siren often buys it, Guardian Angel is not a very good ability for protection against Naga Siren.
* Likewise, Nuker build Naga Siren (which primarly consists of items such as Radiance, Ethereal Blade, Dagon and Veil of Discord) can render Guardian Angel useless. Although Nuker is not a role Naga Siren should be playing.

* Astral Imprisonment wastes Borrowed Time's duration.
* Outworld Destroyer's Sanity's Eclipse can kill Abaddon before Borrowed Time triggers due to the lack of intelligence for Abaddon.

* Song of the Siren completely wastes Abaddon Borrowed Time while keeping him in place.
* Naga Siren is able to simply dispel Abaddon's Curse of Avernus with Mirror Image before getting hit 4 times consecutively.
* Although Naga Siren's illusions can be easily destroyed by Aphotic Shield, Naga Siren can resolve that issue easily by purchasing Heart of Tarrasque to drastically increase her durability. Plus, the said item makes Naga Siren harder to be distinguished from her illusions.

* Most Illusion based heroes (like Chaos Knight and Terrorblade) can't use their illusion beneficially against Sanity's Eclipse's high AoE burst damage.

Additional:
* Arcane Orb deals pure damage against the real Terrorblade, which allows it to bypass his high base armor.
* Arcane Orb and Sanity's Eclipse will make very short work of Terrorblade and his illusions.
* Aghanim's Shard upgraded Astral Imprisonment can be used to save an ally on which Terrorblade has used Sunder.

* Naga Siren can very easily dispel the Reflection with Mirror Image. And Besides Reflection that can be used to detect real Naga Siren, Terrorblade has no other ways to deal with Naga Siren's illusions. And what's worse is that Naga Siren can much easily detect the real Terrorblade due to Conjure Image having illusions having different colors. In addition, Terroblade is not a common Battle Fury nor Mjollnir wielder to counter this problem.
* Aghanim's Scepter upgraded Ensnare will allow Naga Siren to root Terrorblade even ithrough Black King Bar. And with Aghanim's Scepter, Naga Siren can get access to Reel In ability, which can allow her to pull Terrorblade toward herself and her team and away from his illusions, even through Black King Bar.
* Naga Siren can rapidly damage Terrorrblade and weaken Terrorblade's armor with Rip Tide, which combined with Terrorblade's low health and strength gain can almost completely discourage Terrorblade from even being present in teamfights. Rip Tide can also weaken armor of Terrorblade's illusions and damage them.
* Song of the Siren can be used to save an ally whom Terrorblade has used Sunder under the condition Naga Siren is quick enough to do it. And since Terrorblade has no "real" burst damage potential outside from Sunder, Naga Siren will usually have plenty of time to save an allied hero on which Sunder was used. Aghanim's Shard upgraded Song of the Siren can also heal her allies around her for it's duration, which allows Naga Siren to nullify effects of Sunder.
* However, Naga Siren's lack of burst damage can make it difficult for her to burst down Terrorblade before he can use Sunder unless Naga Siren has either Black King Bar or Linken's Sphere to protect herself against it or if she is played as Nuker.
Additional:
* Naga Siren can very easily dispel the Reflection with Mirror Image. And Besides Reflection that can be used to detect real Naga Siren, Terrorblade has no other ways to deal with Naga Siren's illusions. And what's worse is that Naga Siren can much easily detect the real Terrorblade due to Conjure Image having illusions having different colors. In addition, Terroblade is not a common Battle Fury nor Mjollnir wielder to counter this problem.
* Aghanim's Scepter upgraded Ensnare will allow Naga Siren to root Terrorblade even through Black King Bar. And with Aghanim's Scepter, Naga Siren can get access to Reel In ability, which can allow her to pull Terrorblade toward herself and her team and away from his illusions, even through Black King Bar.
* Naga Siren can rapidly damage Terrorrblade and weaken Terrorblade's armor with Rip Tide, which combined with Terrorblade's low health and strength gain can almost completely discourage Terrorblade from even being present in teamfights. Rip Tide can also weaken armor of Terrorblade's illusions and damage them.
* Song of the Siren can be used to save an ally whom Terrorblade has used Sunder under the condition Naga Siren is quick enough to do it. And since Terrorblade has no "real" burst damage potential outside from Sunder, Naga Siren will usually have plenty of time to save an allied hero on which Sunder was used. Aghanim's Shard upgraded Song of the Siren can also heal her allies around her for it's duration, which allows Naga Siren to nullify effects of Sunder.
* However, Naga Siren's lack of burst damage can make it difficult for her to burst down Terrorblade before he can use Sunder unless Naga Siren has either Black King Bar or Linken's Sphere to protect herself against it or if she is played as Nuker.

* Heroes with pure damage can kill Huskar when he inevitably gets low on health: Outworld Destroyer, Silencer.

Additional:
* Outworld Destroyer can dodge Life Break with Astral Imprisonment, leaving him unharmed while Huskar loses HP.
* Sanity's Eclipse can deal massive damage to Huskar before he builds up his Berserker's Blood stacks due to Huskar's low mana pool.

* Mirror Image can cause Huskar to Life Break the wrong target.
* Rip Tide reduces Huskar's already low armor.
* Song of the Siren allows teams to recover from Huskar's initiation, as well as the damage over time from Burning Spears.

* Outworld Destroyer has a huge damage from Arcane Orb, which is why in a 1 on 1 skirmish Storm Spirit simply cannot defeat him in damage. Since Outworld Destroyer will stop gank Storm Spirit with his Astral Imprisonment, and then kill him if he decides to fight
Additional:
* Outworld Destroyer has a huge damage from Arcane Orb, which is why in a 1 on 1 skirmish Storm Spirit simply cannot defeat him in damage. Since Outworld Destroyer will stop gank Storm Spirit with his Astral Imprisonment, and then kill him if he decides to fight

* Ensnare prevents using any kind of movement abiilties, Making Naga Siren good against heroes who rely on gap-closing abilities to escape: Phantom Assassin, Magnus, Slark, Riki, Faceless Void, Storm Spirit.

* Outworld Destroyer is not exceptionally dangerous to Necrohpos because of his Ghost Shroud, but his Astral Imprisonment can save his allies from Necrophos's Reaper's Scythe, though only if he uses it at the right time, If an Outworld Destroyer is nearby, Necrophos should not use Reaper's Scythe unless he has banished himself, or has banished two heroes within 15 seconds

* Illusions make it difficult for Necrophos to target his Reaper's Scythe correctly, thus giving illusion heroes like Chaos Knight or Naga Siren an edge against Necrophos.

* Outworld Destroyer can disrupt Slark's attacks with Astral Imprisonment either by banishing Slark or his target.
* Slark's low heathpool means he will die quickly to Arcane Orb if he is directly attacked by Outworld Destroyer
* Slark has low intelligence gain, making him easy to finish with Sanity's Eclipse if he tries to run with Shadow Dance
Additional:
* Arcane Orb deals pure damage, which ignores the armor granted from permanent agility stacks.
* Astral Imprisonment can disrupt any Pounce attempt by banishing the leashed ally.
* Slark's low mana pool makes him more susceptible to Sanity's Eclipse.

* Ensnare prevents using any kind of movement abiilties, Making Naga Siren good against heroes who rely on gap-closing abilities to escape: Phantom Assassin, Magnus, Slark, Riki, Faceless Void, Storm Spirit.

* Sanity's Eclipse does massive damage to Wraith King who naturally has a low mana pool and typically doesn't build items to increase it.
* Wraithfire Blast's slow projectile speed makes it easy to avoid using Astral Imprisonment.

* Heroes with summons and illusions such as Broodmother and Naga Siren, are ill-suited for Wraith King to fight, as he has no source of waveclear.

* Astral Imprisonment prevents Legion Commander from killing her opponents in Duels.
Additional:
* Outworld Destroyer can save an ally hero caught by Duel with Astral Imprisonment, and he can inflict heavy damage on Legion Commander with Arcane Orb to aid his ally. However, if he gets caught, he is unlikely to survive the duel, due to his lack of durability.

* Song of the Siren lasts long enough to prevent a successful Duel (but only if Naga wasn't the target).

* Most Illusion based heroes (like Chaos Knight and Terrorblade) can't use their illusion beneficially against Sanity's Eclipse's high AoE burst damage.

* Illusion-based and multi-unit heroes can take advantage of Chaos Knight's lack of area damage: Naga Siren, Phantom Lancer, Broodmother

* 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.

* Ensnare prevents using any kind of movement abiilties, Making Naga Siren good against heroes who rely on gap-closing abilities to escape: Phantom Assassin, Magnus, Slark, Riki, Faceless Void, Storm Spirit.

* Any heroes with low mana pools will die quickly or even instantly to Sanity's Eclipse: Doom, Phantom Assassin, Troll Warlord.

* Ensnare prevents using any kind of movement abiilties, Making Naga Siren good against heroes who rely on gap-closing abilities to escape: Phantom Assassin, Magnus, Slark, Riki, Faceless Void, Storm Spirit.

* Astral Imprisonment allows Outworld Destroyer to waste over half of Pierce the Veil, or protect an ally from Dead Shot's fear while also reducing Muerta's maximum mana.
* Sanity's Eclipse will deal massive damage to Muerta if her maximum mana gets too low. And even if she survives it, Sanity's Eclipse's Mana Allergy debuff will discourage her from using abilities as that will result in healing Outworld Destroyer.

* Any long duration disables that can pierce through both, Pierce The Veil and Black King Bar are devastating against Muerta: Enigma's Black Hole, Dawnbreaker's Solar Guardian, Axe's Berserker's Call, Naga Siren's Aghanim's Scepter upgraded Ensnare and Reel In from Aghanim's Scepter, Jakiro's Aghanim's Scepter upgraded Macropyre, Bane's Fiend's Grip, Pudge's Dismember, Batrider's Flaming Lasso, Beastmaster's Primal Roar, Grimstroke's Soulbind, Medusa's Stone Gaze, Magnus's Reverse Polarity.

* Astral Imprisonment protects an ally for much of Rolling Thunder's duration, especially at the lower levels. As Rolling Thunder has a considerable cast animation, an Outworld Destroyer with Blink Dagger can initiate on him and destroy his timing.

* Heroes with powerful rooting abilities will disable most of Pangolier's skills, a bonus point if it pierces spell immunity since it will also be able to stop Pangolier during his Rolling Thunder: Treant Protector, Meepo, Crystal Maiden, Dark Willow, Underlord, Naga Siren

* 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.

* Arcane Orb's pure damage ignores Mars' Bulwark.
* Astral Imprisonment can be used to stop Mars from being disruptive or save allies from his abilities.
* Sanity's Eclipse deals high damage to Mars, due to his low intelligence pool.

* Naga Siren is a natural split-pusher. With Rip Tide, she will easily out-push Nature's Prophet, farming his treants in the process.
* Ensnare prevents Teleportation. Even if he hides inside Sprout, Song of the Siren lasts long enough to prevent him from escaping.
Additional:
* Naga Siren is a natural split-pusher. With a Radiance equipped, she will easily keep the lanes pushed out, therefore keeping backdoor protection enabled and preventing Nature's Prophet from dealing building damage.
* Ensnare can prevent Teleportation. Aghanim's Scepter upgraded Ensnare can also affect Nature's Prophet even if he is spell immune. And Reel In from Aghanim's Scepter can also be used to separate Nature's Prophet from his treant and bring him close to Naga Siren and her team to burst him down.
* Song of the Siren will stop Nature's Prophet from escaping even if he has hidden inside of Sprout. Aghanim's Shard upgraded Song of the Siren can also heal her allies and save them from Nature's Prophet.

* Astral Imprisonment is a versatile nuisance:
* If it is cast on a low-enough-health unit at least 1 second into Shallow Grave's duration, the Shallow Grave will end during the imprisonment, and the target will take lethal damage when released.
* It can be used remove Dazzle from the fight at a time he could have saved someone.
* It lets himself or an ally dodge all of Poison Touch's effects, for long enough to recover their Blink Dagger.

* Mirror Image's illusions can easily walk straight at Dazzle and attack him, due to Dazzle's lack of reliable AoE nukes or disables.
* Ensnare roots Dazzle or his allies, making it harder to stay in range of Dazzle's saving abilities.
* Song of the Siren can be used to initiate a fight with superior positioning, potentially zoning Dazzle's high-impact spells out of the fight.

* Mirror Image can dispel Frostbite. A similar effect can be achieved with Manta Style, a core item on Naga Siren.
* Song of the Siren can stop Freezing Field regardless of any kind of invisibility as well as allow Naga Siren's team to quickly close the gap on Crystal Maiden.
* With Aghanim's Scepter, Naga Siren can get access to Reel In ability, which can allow her to pull Crystal Maiden toward herself and her team and cancel Freezing Field even through Black King Bar.
Additional:
* Mirror Image can dispel Frostbite.
* Song of the Siren can stop Freezing Field regardless of any kind of invisibility as well as allow Naga Siren's team to quickly close the gap on Crystal Maiden.
* Ensnare allows Naga Siren and her team to quickly catch up with Crystal Maiden and kill her.
* With Aghanim's Scepter, Naga Siren can get access to Reel In ability , which can allow her to pull Crystal Maiden toward herself and her team and cancel Freezing Field even through Black King Bar.

* Lycan is a hero focused entirely on single target physical damage and lacks disables or AoE damage. Due to this, he will have difficulties dealing with illusions or Naga Siren's Ensnare.

* Arcane Orb's pure damage, making Counterspell ineffective.
* Sanity's Eclipse will hit Anti-Mage while he is disabled from Astral Imprisonment, and forces him to take heavy damage due to his low intelligence.
* Essence Flux keeps Outworld Destroyer at high mana, thus greatly reducing the damage from Mana Void.
Additional:
* Counterspell doesn't work versus Arcane Orb because it does pure damage.
* Anti-Mage cannot burn all of Outworld Destroyer's mana without disables due to Essence Flux.
* Anti-Mage's Manta Style illusions are quickly destroyed by Arcane Orb.
* However, if the enemy has multiple means of removing mana, Mana Void becomes a threat to Outworld Destroyer, Anti-Mage has better mobility than Outworld Destroyer with Blink, and Counterspell blocks a large portion of the damage from Sanity's Eclipse.

* Sanity's Eclipse deals more damage the less max mana the heroes hit by it have, making Pudge an ideal target.
* Outworld Destroyer can save allies or himself caught by Dismember or Meat Hook with Astral Imprisonment.

* Outworld Destroyer doesn't care if Razor steals his damage because he does most of his damage through Arcane Orb.
* Astral Imprisonment can prevent Razor from using the stolen damage from Static Link or chasing with Eye of the Storm.
* Sanity's Eclipse will do a ton of damage to Razor due to his low mana pool.

* Kraken Shell's dispel does not restore mana lost through Astral Imprisonment, and the stolen mana can really hurt Tidehunter's ability to initiate
* Arcane Orb high pure damage ignores Tidehunter's Armor, and is barely affected by his Kraken Shell's damage block
* It is also completely unaffected by Anchor Smash, due to it relying on Outworlds Mana pool
* Sanity's Eclipse is effective on Tidehunter's poor mana pool, While it is reduced by Kraken Shell, the damage reduction is negligible.

* Astral Imprisonment can be used to protect allies by imprisoning either them or Spirit Breaker.
* Arcane Orb will heavily drain Spirit Breaker's maximum mana, rendering him almost useless and unable to cast spells. And considering how Spirit Breaker's intelligence is very low, Sanity's Eclipse will deal a lot of damage to him.
* Even if Spirit Breaker survives Sanity's Eclipse, mana allergy applied by the Sanity's Eclipse will discourage Spirit Breaker from using his abilities as it will cause him to lose health and heal Outworld Destroyer.

* Heroes with summons and illusions as Spirit Breaker has no strong AoE capabilities to deal with them: Chaos Knight, Phantom Lancer, Terrorblade, Naga Siren, Broodmother, Warlock, Visage, Nature's Prophet, Shadow Shaman, Lycan, Wraith King.

* Outworld Destroyer's pure damage will mop up Primal Split's units very quickly.

* Ensnare and Song of the Siren can be used to cancel both, Tether and Relocate and to close the distance on Io.
* Rip Tide combined with illusions from Mirror Image often finish off Io before he can save himself with Tether or Relocate.
* Spirits's weak area-of-effect makes it a bad tool to deal with Naga Siren's illusions from Mirror Image.
* Once Naga Siren buys Aghanim's Scepter, she can gain access to Reel In, which not only allows her to cancel both, Tether and Relocate, but also to pull Io to herself and her team while he is affected with Ensnare, similarly to Batrider's Flaming Lasso.
* Aghanim's Shard upgraded Song of the Siren can also heal the hero Io and his Tethered targed try to gank.
Additional:
* Ensnare and Song of the Siren can be used to cancel both, Tether and Relocate and to close the distance on Io.
* Rip Tide combined with illusions from Mirror Image often finish off Io before he can save himself.
* Spirit's weak area-of-effect makes it a bad tool to deal with Naga Siren's illusions from Mirror Image.
* Once Naga Siren buys Aghanim's Scepter, she can gain access to Reel In, which not only allows her to cancel both, Tether and Relocate, but also to pull Io to herself and her team while he is affected with Ensnare, similarly to Batrider's Flaming Lasso.
* Aghanim's Shard upgraded Song of the Siren can also heal the hero Io and his tethered targed try to gank.

* Outworld Destroyer can steal more mana with Astral Imprisonment from Skywrath Mage with Shield of the Scion (granted by Aghanim's Shard). Shield of the Scion grants Skywrath Mage bonus intelligence every time he deals magic damage to an enemy hero with his abilities. The higher his intelligence, the larger his mana pool. Since Astral Imprisonment steals based on the target's max mana, Outworld Destroyer can steal much more mana from Skywrath Mage.

* Naga Siren can easily disjoint, and dispel Corrosive Skin with Mirror Image.
* Since Viper is mostly a single-target hero, he will not have almost any chance against Naga Siren because she is an illusion based hero.
* Viper has no burst damage, so Naga Siren will have plenty of time to use Aghanim's Shard upgraded Song of the Siren heal her allies before Viper can finish them off.

* Astral Imprisonment can allow Outworld Destroyer to save himself or allies from Kunkka's full kit.
* Sanity's Eclipse deal a large amount of damage, as Kunkka's mana pool is much smaller than Outworld Destroyer's.
* Arcane Orb deals pure damage, shredding through Kunkka and his team even with Ghostship's buff.

* Outworld Destroyer's pure damage from Arcane Orb can go through Cold Embrace.
* Outworld Destroyer can negate the healing from Cold Embrace using Astral Imprisonment, and steal mana while doing so.
* Outworld Destroyer's damage during Winter's Curse is reduced due to Arcane Orb being unable to target allies.
Additional:
* Winter Wyvern must never put her allies in Cold Embrace against Outworld Destroyer as Arcane Orb will continue to deal damage to the defenseless hero.
* Arcane Orb does not hit his allies when he is taunted by Winter's Curse, making it weak against allies, but strong versus enemies.
* Astral Imprisonment can protect a target inflicted with Winter's Curse.

* Naga Siren's illusions from Mirror Image can depush the lanes pushed by the Tempest Double, relieving the pressure.
* Mirror Image can dispel Flux, and the illusions can stop Flux from working to it's full power.
Additional:
* Song of the Siren stops Arc Warden from acting and allows Naga Siren's team to close in on him, past his Magnetic Field.
* Mirror Image dispels Flux. The illusions created from it also disable the slow from Flux if Arc Warden casts it after Mirror Image.
* Arc Warden's playstyle heavily favors split-pushing, which Naga Siren can compete against with her illusions.

* Heroes with summons like Broodmother, Enigma, Nature's Prophet; or illusions, like Naga Siren, Terrorblade are effective at keeping the choke points and rune spawns safe from Proximity Mines.

* Heroes that can protect or dispel stunned allies such as Legion Commander, Outworld Destroyer, Shadow Demon and Oracle can reduce the effectiveness of Sacred Arrow.

* Illusion heroes like the aforementioned Phantom Lancer or Naga Siren, or heroes that tend to buy Manta Style, like Luna or Juggernaut, will give Slardar a hard time, as his damage is single-targeted.

* Ensnare prevents using any kind of movement abiilties, Making Naga Siren good against heroes who rely on gap-closing abilities to escape: Phantom Assassin, Magnus, Slark, Riki, Faceless Void, Storm Spirit.

* Any heroes with low mana pools will die quickly or even instantly to Sanity's Eclipse: Doom, Phantom Assassin, Troll Warlord.

Additional:
* Outworld Destroyer's pure damage from Arcane Orb is very effective at killing Troll Warlord quickly.
* Astral Imprisonment removes Troll Warlord from a fight for four seconds, minimizing his contribution to a teamfight, and potentially wasting over half of Battle Trance's duration.
* Troll Warlord gains a measly 1 intelligence point per level, meaning Sanity's Eclipse is especially effective, often instantly killing him.

* Naga Siren with Mirror Image
* Heroes that can dodge Glimpse:
* Puck with Phase Shift
* Riki with Tricks of the Trade
* Phantom Lancer with Doppelganger
* Ember Spirit with Sleight of Fist and Activate Fire Remnant
* Chaos Knight with Phantasm
* Naga Siren with Mirror Image
* Tusk with Snowball
* Juggernaut with Omnislash
* Brewmaster with Primal Split
* Lifestealer with Infest
* Phoenix with Supernova

* Heroes with hiding abilities can protect disabled allies: Outworld Destroyer, Shadow Demon, Tusk, Phoenix with Aghanim's Scepter.

* Heroes with illusions and summons can swarm and overwhelm Bane, who has no area abilities to deal with them outside from Aghanim's Shard upgraded Brain Sap: Broodmother, Chaos Knight, Naga Siren, Nature's Prophet, Phantom Lancer, Terrorblade, Visage, Warlock, Wraith King.

* Naga Siren with Mirror Image
* Heroes that can remove the Track debuff with their skills:
* Abaddon with Aphotic Shield and Borrowed Time
* Huskar with Life Break
* Juggernaut with Blade Fury
* Legion Commander with Press the Attack
* Lifestealer with Rage and Infest
* Naga Siren with Mirror Image
* Omniknight with Heavenly Grace
* Oracle with Fortune's End and False Promise
* Phantom Lancer with Doppelganger
* Slark with Dark Pact
* Ursa with Enrage
* Weaver with Time Lapse
* Tidehunter with Kraken Shell when damage received reaches the threshold.

Additional:
* Bounty Hunter is a single target damage dealer, so he will not fare well against Naga Siren. Even though Bounty Hunter can use Track on her, Mirror Image will dispel the effect. Ensnare also reveals invisible units while they're rooted, putting Bounty Hunter at a disadvantage.

* Ursa struggles against heroes with strong (and especially undispellable) disables (Disruptor, Puck, Shadow Demon, Outworld Destroyer and etc).

* Astral Imprisonment allows Outworld Destroyer to save himself or ally from Invoker's combo, or remove Invoker from a fight temporarily.
* Arcane Orb's pure damage will deal a lot of damage against Invoker's mediocre strength gain.
* E.M.P. is useless against Outworld Destroyer by activating Equilibrium.
* However, be aware that Sanity's Eclipse will most likely not deal any damage at all, due to Invoker's high intelligence gain compared to Outworld Destroyer's.

* Arcane Orb's constant pure damage output is devastating to Dragon Knight.
* Dragon Knight's relatively low mana pool leads to heavy damage from Sanity's Eclipse, which also bypasses his armor.

* Song of the Siren does not affect Supernova, which allows her and her team to focus the egg while the enemy team is affected by sleep.
* Phoenix cannot use Icarus Dive for escaping when rooted by Ensnare.
* However, Phoenix has many area-of-effect abilities that allow him to clear Naga Siren's illusions from Mirror Image.

* Astral Imprisonment can save allies from a Black Hole combo. When upgraded with Aghanim's Scepter and Aghanim's Shard, it becomes exceedingly difficult for Enigma to land a good Black Hole against Outworld Destroyer and his team.
* Astral Imprisonment can also cancel Black Hole while Enigma does not have Black King Bar.
* Arcane Orb and Sanity's Eclipse can often make a short work out of Enigma and his Eidolons.

* The pure damage provided by Arcane Orb is a great addition for killing Ember Spirit.
* Astral Imprisonment fully negates all magic damage of Flame Guard and Searing Chains and will temporarily save himself from Sleight of Fist's physical damage, and Ember Spirit is not a hero that can counter these skills.

* Mirror Image can be effective since Night Stalker cannot withstand fighting illusions. If he's unable to tell which Naga Siren is real, he will have a hard time landing his Void. However, if Night Stalker obtains an Aghanim's Scepter, the upgraded Void will hit and may even locate the real Naga Siren in fights.
Additional:
* Ensnare and Song of the Siren prevents Night Stalker from escaping and ganking during daytime or even nighttime.
* Rip Tide reduces Night Stalker's armor, making him easier to focus down.
* Mirror Image can be effective against Night Stalker, due to his single target abilities.

* Every hero that can withstand or prevent Eclipse at level 7: Juggernaut, Riki, Clockwerk, Drow Ranger, Abaddon, Faceless Void, Weaver, Outworld Destroyer.

* Heroes that create illusions: Spectre, Shadow Demon, Phantom Lancer, Naga Siren, Chaos Knight, Terrorblade) or bring other units into the fight (such as Nature's Prophet, Lone Druid, Chen, Enchantress, Meepo and Arc Warden) can cause Eclipse to strike the illusions/summons unintentionally. However, in many cases Moon Glaives can resolve this issue and eliminate them before activating Eclipse, but that will require lots of farming for right-click items.

* 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:
* Arcane Orb's pure damage can do great damage to Underlord.
* Sanity's Eclipse can tear down Underlord's health by a large amount, since his mana pool is very low compare to Outworld Destroyer's high mana pool.

* Heroes with strong area-of-effect damaging and/or disabling abilities will be able to intercept Underlord and his team when they exit from Fiend's Gate: Luna's Aghanim's Scepter upgraded Eclipse, Dawnbreaker's Solar Guardian, Axe's Berserker's Call, Mars's Arena of Blood, Jakiro's Macropyre, Dual Breath and Ice Path, Naga Siren's Song of the Siren, Razor's Eye of the Storm and Plasma Field, Lina's Light Strike Array, Broodmother's Spinner's Snare from Aghanim's Scepter, Elder Titan's Earth Splitter and Echo Stomp, Alchemist's Unstable Concoction and Acid Spray, Queen of Pain's Sonic Wave, Dark Seer's Wall of Replica and Vacuum, Venomancer's Noxious Plague and Poison Nova from Aghanim's Scepter, Oracle's Fortune's End and Rain of Destiny from Aghanim's Shard, Bloodseeker's Blood Rite, Enigma's Black Hole and Midnight Pulse, Shadow Fiend's Requiem of Souls, Batrider's Aghanim's Scepter upgraded Flaming Lasso, Firefly, Flamebreak and Sticky Napalm, Ancient Apparition's Ice Blast, Sand King's Epicenter, Sand Storm and Burrowstrike, Gyrocopter's Call Down, Ember Spirit's Sleight of Fist, Death Prophet's Exorcism and Silence, Monkey King's Wukong's Command, Crystal Maiden's Freezing Field, Muerta's The Calling, Medusa's Stone Gaze, Zeus's Nimbus from Aghanim's Scepter. Dark Willow's Bramble Maze, Pangolier's Swashbuckle, Grimstroke's Soulbind, Ink Swell and Stroke of Fate, Earthshaker's Echo Slam and Fissure, Puck's Dream Coil and Waning Rift, Winter Wyvern's Winter's Curse, Magnus's Reverse Polarity.

* Arcane Orb deals pure damage, effectively bypassing Morphling's high armor from Attribute Shift (Agility Gain).
* Sanity's Eclipse is more effective against a low health and mana pool Morphling, enabling Outworld Destroyer to burst Morphling down before he can shift to Strength.
Additional:
* Arcane Orb deals high damage regardless of Morphling's high armor from Attribute Shift (Agility Gain).
* Because of Morphling's very low intelligence gain and base intelligence, Sanity's Eclipse will almost always be effective against Morphling.

* Any heroes with low mana pools will die quickly or even instantly to Sanity's Eclipse: Doom, Phantom Assassin, Troll Warlord.

* 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.

* Ensnare with her attacks allows Naga Siren to gank Sniper easily.
* Rip Tide removes Sniper's very little armor.

* Song of the Siren is very difficult for Rubick to Spell Steal when he is affected by sleep.
* Ensnare and Rip Tide together with some attacks can take Rubick down quickly, due to his low health pool and armor.
* Naga Siren usually buys Diffusal Blade, which may prevent Rubick from using his abilities.
* Mirror Image allows Naga Siren to dodge the incoming stun from Telekinesis (when she is not a target), and it can also dispel Fade Bolt's damage reduction debuff.

* Arcane Orb's pure damage ignores Timbersaw's Reactive Armor.
* Astral Imprisonment, if timed correctly, can interrupt Timber Chain, preventing him from escaping.
Additional:
* Arcane Orb deals constant pure damage, which bypasses Timbersaw's Reactive Armor.
* Sanity's Eclipse can hit targets inside Astral Imprisonment, which helps Outworld Destroyer finish off Timbersaw before he escapes with Timber Chain. It can also drain his mana, limiting his ability to escape should he survive.

* Primal Beast is mostly played in the offlane role, so picking a carry who can escape from him is essential. Heroes such as Troll Warlord, Lone Druid and Outworld Destroyer, or generally any carry with a stun, slow or ability to fight back will stop him from having the good start he needs.

* Astral Imprisonment can be used to protect allies from Jakiro's various abilities, It can also be cast on Jakiro to break his combos (Macropyre into Ice path into Dual Breath), while at the same time, stealing his much needed mana.
* Aghanim's Shard upgraded Astral Imprisonment allows Outworld Destroyer and his allies to move while imprisoned, which allows them to leave the area of Jakiro's abilities.
* As Outworld Destroyer is prone to buying Meteor Hammer, he can combine it with Astral Imprisonment and Arcane Orb's high pure damage that can quickly decimate Jakiro, And unlike most heroes, Outworld doesn't particularly care who he targets.
* Outworld is also a common Black King's Bar carrier, and Jakiro's only tool to counter it is the Aghanim's Scepter upgraded Macropyre

* Astral Imprisonment allows Outworld Destroyer to save himself or his teamates during Omnislash.
* Juggernaut's low mana from his low intelligence gain means that he'll take a lot of damage from Sanity's Eclipse.

* Illusion-based heroes are effective against Omnislash and Juggernaut's single-targeted damage: Naga Siren, Chaos Knight, Terrorblade,Phantom Lancer.

* Outworld Destroyer's pure and magical damage is particularly effective against Earthshaker.
* Astral Imprisonment catches Earthshaker while he blinks in, preventing him from executing his combo.
* Earthshaker has mana troubles, and Outworld Destroyer's abilities can press this by stealing intelligence comes from Arcane Orb, therefore depleting his mana pool and mana regeneration.
* Sanity's Eclipse deals high damage to Earthshaker, due to his low intelligence and mana pool.

* Heroes with illusions: Chaos Knight, Naga Siren, Phantom Lancer, Terrorblade

* 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.

* Outworld Destroyer's pure and magical damage is particularly effective against Axe.
* Astral Imprisonment is an excellent way to defend against an initiating Axe.
* Sanity's Eclipse deals high damage to Axe due to his low mana pool.
Additional:
* Berserker's Call bonus armor doesn't block Arcane Orb's pure damage.
* Astral Imprisonment can be used to prevent an ally or Outworld Destroyer himself from an Axe initiation.
* Axe's low mana means he's susceptible to a powerful Sanity's Eclipse.

* Illusion heroes, such as Naga Siren, Phantom Lancer, Chaos Knight, Terrorblade will become strong against Tinker in the late game. Without Aghanim's Scepter Tinker is forced to defensively disarm heroes with Laser, leaving illusions free to deal physical damage which Tinker's low armor makes highly effective. In addition, Mjollnir or Battle Fury, two common pickups against illusion heroes, don't work well on Tinker at all.