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

* 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.

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

* 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 and Crippling Fear.
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.

* Leshrac's AoE abilities make quick work of Chen's creep army.

* 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.

* Heroes who summon multiple units that are not spell immune. Nature's Prophet,Lycan,Beastmaster

* Lycan is a carrier built entirely with physical attacks, having 0 AoE presence and no spell power. Due to this, he can't deal with illusions or Naga Siren's Ensnare.

* Heroes that have disposable area-targeted spells can force her to undo her Meld: Leshrac, Puck, Tiny. An experienced Templar Assassin could try to Refraction before Meld so she can tank through those damage without getting her Blink disabled.

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

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

* Leshrac's AoE abilities destroy Phantom Lancer's illusions.
* Diabolic Edict and Pulse Nova require no targeting, thus hitting Phantom Lancer whenever he's nearby.
Additional:
* Leshrac can easily clear Phantom Lancer's illusions with his huge area of effect damage.

* 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 will prevent Rubick from spamming his abilities from Spell Steal.
* Mirror Image allows to dodge the incoming stun from Telekinesis (when she is not a target) and it can also to dodge and dispel Fade Bolt's damage reduction debuff.

* Diabolic Edict and Pulse Nova will tear apart any illusions spawned from Disruption
* Split Earth can punish improper usage of Disruption.
* Leshrac does not have any buffs that can be removed by Demonic Purge.
Additional:
* Pulse Nova makes quick work of any illusions with amplified damage, and deals damage even if Leshrac is in Disruption.
* An attempt to save an ally using Disruption can easily become a perfect setup for a Split Earth for the enemy.
* Disruption does not stop Diabolic Edict and Pulse Nova once they start pulsing, and even worse it provides a safe shelter for Leshrac to keep pumping up his powerful AoE damage onto the battlefield.
* Leshrac usually builds Eul's Scepter of Divinity to dispel Shadow Poison and Soul Catcher and Linken's Sphere to block Disruption and Demonic Purge.
* Shadow Demon doesn't have the burst damage to take Leshrac out of the fight quickly, although Demonic Purge can help his allies kill a squishy Leshrac.

* 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 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.

* Lightning Storm will usually hit both Io and its tethered target since both will be close enough for the lightning to jump.
* Diabolic Edict and Pulse Nova hit all units near Leshrac, meaning he can do colossal damage to Io and its tethered target.
Additional:
* Lightning Storm will usually hit both Io and his Tethered target since both will be close enough for the lightning to jump. It can then be followed up by Split Earth.
* Diabolic Edict and Pulse Nova hit all units near Leshrac, meaning he can do colossal damage to Io and his Tethered target.

* 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.

* 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.

* 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 is one of the most natural Diffusal Blade carriers, the bane of every hero with a small mana pool.

* 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 tankiness. Plus, the said item makes Naga Siren harder to be distinguished from her illusions.

* Diabolic Edict and Pulse Nova hit all units around Leshrac, making it very easy for him to kill the Summon Familiars.
* Diabolic Edict and Pulse Nova also deal many instances of damage, nullifying Gravekeeper's Cloak.
* Split Earth and Lightning Storm makes it difficult for Visage to kite Leshrac, even while under the effects of Grave Chill.

* Song of the Siren stops him from acting and her illusions can push better than him because Mirror Image has a longer duration.
* Arc Warden does not often build Radiance, which is useful for illusions and countering illusion pushes.
* Mirror Image dispels Flux or prevents Flux's slow.
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.

* Ensnare is good vs bear.
* In teamfights, song of the siren may be used to properly set up and coordinate an attack on Lone Druid in the backline, bursting him down, allowing to completely ignore the bear.
* Druid lack innate AoE capabilities giving him no good way of dealing with illusions.

* Your AoE abilities should make quick work of her spiderlings.

* 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.

* Heroes with AoE abilities will hit Slark in Shadow Dance: Lina, Jakiro, Underlord, Leshrac, Dark Seer, Earthshaker, Timbersaw, Crystal Maiden

* 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.

* 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 wide AoE abilities will reveal Monkey King through Mischief: Necrophos, Phoenix, Alchemist, Earthshaker, Razor, Tinker, Leshrac, Queen of Pain

* 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

* 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.

* Any hero reliant of mobility, like Storm Spirit.

* Since Windranger is bad against magical damage, heroes with continuous magical damage or magical nukes can blast her: Zeus, Tinker, Leshrac, Viper, Skywrath Mage, Lion, Lina, Venomancer.

* 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 dealer, so he will not fare well against Naga Siren. He might as well try to Track her, but her Mirror Image will dispel the effect. Also, Ensnare reveals invisible units while they're rooted, putting Bounty Hunter in a tricky situation.

* 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.

* 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.

* 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 summon multiple units that are not spell immune. Nature's Prophet,Lycan,Beastmaster

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

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

* Pulse Nova deals an insane amount of damage in an area around him, which can quickly wear down Meepo clones.
* Leshrac can catch multiple Meepos in Split Earth and follow up with the rest of his area damage spells making meepo unable to get close to leshrac.
* Diabolic Edict is a strong ability that can wear down a lone Meepo clone quickly.

* 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.

* 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.

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

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