* Gush can make Crystal Maiden's already weak armor even weaker.
* Kraken Shell can dispel Frostbite, preventing him from getting stuck inside Freezing Field.
* Ravage is very useful for interrupting Freezing Field, even while Crystal Maiden is under the effects of Glimmer Cape. Crystal Maiden must purchase a Black King Bar, which is far more costly.

* 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.
Additional:
* Mirror Image can dispel Frostbite.
* Ensnare and Song of the Siren can stop Freezing Field.
* Song of the Siren can allow her team to quickly close the gap on Crystal Maiden.

* Most summons and illusions can barely hurt Tidehunter at all, after their attacks get reduced by Anchor Smash and blocked by Kraken Shell: Nature's Prophet, Enigma
* Also Ravage's large area of effect and damage can easily damage all those units at once, or just straight up clear them.

* Naga Siren is a natural split-pusher. With a Radiance equipped, she will easily out-push Nature's Prophet, farming his treants in the process.
* Ensnare prevents Teleportation. Even if he hid inside Sprout, Song of the Siren lasts long enough to prevent him from escaping.
Additional:
* 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.

* Ravage damages and disables Chaos Knight's army.
* Anchor Smash deals respectable area damage at early levels and lowers Chaos Knight's damage.
* Kraken Shell dispels Chaos Bolt and Reality Rift while providing protection from damage.

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

* Lycan is a hero focused entirely on single target physical damage and lacks disables or AoE damage. Due to this, he can't deal with illusions or Naga Siren's Ensnare.

* Kraken Shell grants him massive physical attack protection
* Anchor Smash will wipe the area, clearing Lycan's wolves.

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

* 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,Drow Ranger.

* Tidehunter's Kraken Shell dispels Corrosive Haze and Bash of the Deep's stun if enough damage is taken. Anchor Smash and Kraken Shell's damage block also reduces Slardar's damage.

* 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.

* Tidehunter with Kraken Shell when damage received reaches the threshold.
* 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.

* 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. He may try to Track her, but her Mirror Image will dispel the effect. Ensnare also reveals invisible units while they're rooted, putting Bounty Hunter at a disadvantage.

* Vengeful Spirit should carefully consider whether to use her Nether Swap on Tidehunter, as it can easily position him for a Ravage on Vengeful Spirit and her allies.
* Due to Magic Missile's high damage, Kraken Shell will often proc and clear Tidehunter's debuffs.

* Unless Lone Druid purchases a Black King Bar for his Spirit Bear, Ensnare will easily kite the Bear.
* Song of the Siren allows Naga Siren and her team to completely bypass the Spirit Bear and hunt for the 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.

* Kraken Shell dispels both Shadowraze's damage amplification stacks and Requiem of Soul's damage reduction (provided Tidehunter has taken enough damage).
* Ravage cancels Requiem of Souls if Shadow Fiend isn't protected by Black King Bar.
Additional:
* Kraken Shell dispels the damage amplification stacks of Shadowraze as well as the damage reduction from Requiem of Souls (provided he has taken enough damage).
* Anchor Smash reduces Shadow Fiend's large attack damage, Kraken Shell makes Tidehunter the last target Shadow Fiend wants to attack.
* Ravage can easily cancel Requiem of Souls if Shadow Fiend isn't protected by Black King Bar.

* Gush reduces Pudge's armor which he already lacks.
* Kraken Shell can dispel Dismember after reaching a certain threshold of damage.
* Tidehunter's naturally high health, strength gain, and common itemization for survivability through magic resistance make Tidehunter a poor target.

* Kraken Shell dispels the stun from Paralyzing Cask. However, it does not dispel the damage from Maledict.
* Once Witch Doctor first uses his Death Ward in team fights, Tidehunter can simply cancel it with Ravage, turning the tables against him, especially if Witch Doctor does not have a Black King Bar.
* As a precaution, let Tidehunter use Ravage first before channeling Death Ward to turn a team fight in your favor.

* Song of the Siren can be used to time out Guardian Angel, giving Naga Siren's team an easy opportunity to counter-initiate.
Additional:
* Song of the Siren will waste Guardian Angel.
* Ensnare fully works on Heavenly Graced targets. 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.

* 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.

* Song of the Siren can be used to nullify the effects of Winter's Curse, and when upgraded with Aghanim's Scepter it also outmatches the heal of Cold Embrace.
* If Winter Wyvern is reckless enough to put an ally in Cold Embrace, Naga Siren will be able to use her Ensnare to extend the disable on the hero affected by Cold Embrace.

* Kraken Shell and Anchor Smash makes it very difficult for Phantom Lancer's illusions to damage to Tidehunter.
* Ravage will stun the real Phantom Lancer while clearing most of his illusions.
* Anchor Smash reduces base damage, which is the majority of Phantom Lancer's auto-attack damage.
* An Aghanim's Scepter upgraded Gush slows down and reduces all of Phantom Lancer's illusions.
Additional:
* A dozen of Phantom Lancer's illusions with all their might can barely hurt Tidehunter at all thanks to Kraken Shell and Anchor Smash. The only way Phantom Lancer can hurt Tidehunter is through the mana burn provided by Diffusal Blade.
* Even with high chasing power from Spirit Lance and Phantom Rush (and even Diffusal Blade), Tide Hunter can shrug it all off with Kraken Shell and escape by using a Town Portal Scroll or just moving away.
* The AoE nukes from Ravage, Anchor Smash, and an Aghanim's Scepter-upgraded Gush can clear Phantom Lancer's illusions easily.

* 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.

* 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.

* 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.

* Kraken Shell makes Tidehunter take nearly no damage from Spiderlings.
* Anchor Smash kills Spiderlings in one or two casts, should Broodmother try to swarm Tidehunter with them.

* 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.
Additional:
* Her illusions can push better than Arc Warden's Tempest Double because Mirror Image has a longer duration.
* Mirror Image dispels Flux, and the illusions stop Flux from working.

* Kraken Shell dispels Fiend's Grip, wasting it easily.

* Visage's Familiars cannot penetrate Kraken Shell and will do almost no damage to Tidehunter even with Medallion of Courage or Solar Crest.
* Anchor Smash's bonus damage has the potential to kill Familiars.

* 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.

* 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.

* Tidehunter's Anchor Smash decreases Drow Ranger's attack damage.

* Heroes with summons like Broodmother,Enigma, Invoker, Nature's Prophet, Lycan, Visage;or illusions, like Naga Siren, Phantom Lancer, Terrorblade are effective at keeping the choke points and rune spawns safe from Proximity mines in the early game.

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

* Any hero reliant of mobility, like Storm Spirit.

* Multiple attackers thanks to illusions: Phantom Lancer, Chaos Knight, Naga Siren (bonus for her Ensnare). Also despite the visual effects, Templar Assassin does not spill damage against illusions or buildings, so she is not a really good hero to clean up illusions.
* Heroes that can quickly deal damage to her, regardless of how weak they are, can easily break through her Refraction:
* Multiple attackers thanks to summoned units or clones: Meepo, Witch Doctor, Lycan, Enigma, Shadow Shaman
* Multiple attackers thanks to illusions: Phantom Lancer, Chaos Knight, Naga Siren (bonus for her Ensnare). Also despite the visual effects, Templar Assassin does not spill damage against illusions or buildings, so she is not a really good hero to clean up illusions.
* Weak damage but high tick rate or persist in a long time: Slark, Gyrocopter, Queen of Pain, Shadow Shaman (Shackles), Pugna

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

* 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.

* Illusion and heroes with summons are difficult to kill with Chen's single-target offensive spells: Terrorblade, Phantom Lancer, Chaos Knight, Broodmother, Naga Siren, Lycan, Visage. However, Chen can convert enemy summons with Holy Persuasion, as long as they don't bunch up.

Additional:
* Naga Siren can make landing Chen's combo very hard due to her being an illusion hero.
* Ensnare will prevent Chen from activating Hand of God.

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

* Heroes that excel at grouping up with their team very early will be able to take advantage of a Clinkz that tries to pick off heroes that are alone: Brewmaster, Dazzle, Tidehunter.

* Illusion heroes, such as Naga Siren, Phantom Lancer, Chaos Knight, Terrorblade will become strong against Tinker in the late game when Tinker's only area of effect damage, March of the Machines, ceases to kill illusions quickly. 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.

* Song of the Siren is very difficult for Rubick to Spell Steal when he is affected by sleep. However, if Rubick does successfully steal it, the Song will allow his team to initiate from unexpected angles.
* 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.

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

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

* Kraken Shell easily dispels the lengthy stun from Shackleshot.
* Kraken Shell (and possibly Anchor Smash) blocks huge amount of damage from Focus Fire.
* Anchor Smash is one of the few sources of True Strike, which means Tidehunter can deal significant damage through Windrun, while also reducing Windranger's damage output.

* Ravage, being an AoE disable, cancels Epicenter's channeling from a long range, limiting his potential to counter-initiate.
* This can be remedied, however, by first using a Black King Bar, then channel Epicenter, then finally initiate with Blink Dagger.

* Heroes that rely on base damage: Luna, Phantom Lancer are easily countered with Anchor Smash.

* Heroes that create illusions (such as 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 and the aforementioned 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).

* Heroes who can stun multiple units at once: Dark Willow, Spirit Breaker, Slardar, Invoker, and Tidehunter.

* Kraken Shell is very useful against Sticky Napalm and Flamebreak, easily dispelling them regularly.
* Tidehunter is probably the worst hero to target with Flaming Lasso, as Kraken Shell will remove it and Tidehunter often survives long enough to cast Ravage in the middle of Batrider's team. At the same time, if Batrider initiates on his teammate, Tidehunter will have the perfect opportunity to counter-initiate.
Additional:
* Kraken Shell can dispel Flaming Lasso.
* If Batrider drags Tidehunter back towards his team, it can be setup for a well placed Ravage.

* Naga Siren can easily disjoint, and dispel Corrosive Skin with Mirror Image.
* Since Viper is a single-target hero, he will not stand a chance against Naga Siren because she is an illusion based hero.
* However, Nethertoxin can clear her illusions quickly if Naga Siren does not micromanage them well.

* Heroes with powerful rooting abilities will disable most of Pangolier's skill, a bonus point if it pierce 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

* Tidehunter naturally has a high health pool and thus makes it hard for Lion to burst him down. Kraken Shell further mitigates this by dispelling any disables Lion casts when Tidehunter takes enough damage.
* Gush and Ravage can both not only burst Lion down, but also catch him out and prevent him from escaping.

* Durable heroes: Axe, Bristleback, Tidehunter, Wraith King