* Viper's damage over time and lack of disables makes him easy to Sunder.
* Viper's physical damage is mitigated by Terrorblade's high armor.
* Terrorblade under Metamorphosis can quickly kill Viper with heavy physical damage.
Additional:
* Almost all of Viper's damage revolves exclusively around single-target damage-over-time effects. Furthermore, without any hard disables, Terrorblade can almost always get a Sunder off.
* Viper has low mobility and Corrosive Skin doesn't protect against physical damage, which means that Terrorblade under Metamorphosis can quickly kill Viper.

* 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.

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

* Sunder can save himself or his allies from Assassinate.
* Sniper relies on right-clicks to deal damage, and Terrorblade's high armor can reduce his damage by quite a bit.
* Terrorblade is a far harder carry than Sniper is, so a well-farmed Terrorblade can easily defeat a Sniper.

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

* Terrorblade's illusions and ranged attacks in Metamorphosis can burst down Lifestealer very quickly.
* Terrorblade has low health due to his low strength gain, which reduces Feast's lifesteal and damage.
* Terrorblade's high armor makes Lifestealer's Desolator useless.
* Because Lifestealer usually walks around with high HP in fights due to his lifesteal (and sometimes Armlet of Mordiggian), he is a great target for Terrorblade's Sunder.
Additional:
* Reflection's illusion carries Feast as well, making it useful in fights.
* Feast cannot compensate for Terrorblade's incoming high damage, due to his low Strength gain.
* Open Wounds is a lot harder to land on the real Terrorblade if he has illusions around him.
* Lifestealer relies on right-clicks to deal damage, and Terrorblade's high armor can reduce his damage by quite a bit.

* 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.

* Sunder can prevent Terrorblade's or an ally's death by swapping health, making damage-over-time spells inefficient. Heroes that rely on damage-over-time abilities like Venomancer and Huskar will have a hard time against Sunder.

* 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.

* Heroes with illusions and summons can manfight Night Stalker: Terrorblade, Beastmaster, Broodmother.

* Wraith King has no form of AoE to clear Terrorblade's illusions.
* Terrorblade is a common Manta Style and Diffusal Blade carrier.
* Terrorblade has very high armor, which helps against Wraith King's physical-only damage.
* A reincarnated Wraith King is an ideal target for Sunder if Terrorblade's health is low.

* 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 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 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.

* 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 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.

* 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.

Additional:
* Techies' mines can be destroyed by Terrorblade's spammable illusions.
* Terrorblade can push without the fear of dying to mines; he can instead use his illusions to push.

* 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.

* 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.

* Terrorblade starts out with and gains a lot of armor from his agility growth. His illusions also make it difficult for Slardar to focus down the real Terrorblade.

* Terrorblade is one of the strongest carries in the late game, due to his resilience against physical damage, which can be a problem for almost every strong burst physical damage carries, such as Phantom Assassin and Templar Assassin.

* 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.

* 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.

* The Reflection of Shadow Fiend cause Presence of the Dark Lord to affect Shadow Fiend, reducing his armor and making it easier for Terrorblade to kill him. Shadow Fiend also doesn't have lots of survivability or control skills in order to escape.
* If Shadow Fiend chooses to go for a right-click build, he'll have a hard time against Terrorblade's high armor.

* Pudge has low armor and low mobility, making him a prime target for Terrorblade's right-clicks.
* Meat Hook is a lot harder to land on the real Terrorblade if he has illusions around him.
* Because Dismember targets only one hero, Terrorblade's illusions can potentially save the real Terrorblade if he's caught in it.

* Witch Doctor's Maledict burst damage can be prevented by Sunder, if timed correctly.
* Death Ward deals physical damage, and Terrorblade's high armor can help him survive against Death Ward.
* However, be careful that Paralyzing Cask is commonly tricky to dodge as Terrorblade, due to his reliance of illusions, and Maledict can kill Terrorblade if he has no target to be Sundered with, especially in the early game.

* 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.

* Terrorblade with Manta Style and Conjure Image illusions overwhelms Anti Mage.
* Reflection turns Mana Break against Anti-Mage draining his mana making it useful in fights.
* Terrorblade's low mana pool makes him a poor target for Mana Void.
Additional:
* Reflection's illusion carries Mana Break as well, making it useful in fights.

* If Terrorblade's health gets low enough, Terrorblade's Sunder can be used to completely deplete Spectre's health pool without any consequences from Dispersion.
* Terrorblade is one of the few late game heroes that can stand toe to toe and man fight Spectre. Not all is lost if the game goes late when Terrorblade is on your team against Spectre.

* 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.

* 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.

* Reflection illusion will apply Poison Sting to you if hit.
* Conjure Image and Metamorphosis will make quick work of your Plague Wards.
* While ticking down from your poison, Terrorblade can wait until the last possible moment to Sunder a target, either friend or foe.

* 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.

* Sunder is not affected by Ice Blast and will still swap health with any target as usual.
Additional:
* Sunder allows Terrorblade (or an ally) to regain HP while affected by Ice Blast.
* Terrorblade often buys Manta Style which can dispel Cold Feet

* Terrorblade can use Sunder to save his allies who are Doomed.

* Terrorblade's Sunder is not affected by the Bristleback damage reduction.

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

* 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

* Terrorblade can destroy Tombstone with his Conjure Image and Metamorphosis.

* 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 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 with high base damage (Morphling, Tiny, Drow Ranger), heroes with mana burning abilities (Anti-Mage), and Diffusal Blade users (Juggernaut or Riki) will suffer from Reflection's illusions.

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

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

* Heroes that can overwhelm Visage by sheer number like Chaos Knight, Meepo, Terrorblade and Phantom Lancer.

* 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.

* 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.

* Conjure Image and Reflection illusions may give Clockwerk a hard time to find an angle for Hookshot.
* A trapped Terrorblade can turn the tables with Sunder, leaving Clockwerk nowhere to run.

* 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.

* 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.

* 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.

* 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 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.

* Terrorblade is one of the strongest carries in the late game, due to his resilience against physical damage, which can be a problem for almost every strong burst physical damage carries, such as Phantom Assassin and Templar Assassin.

* 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.

* Heroes with illusions and summons can swarm Bane, who has no area abilities: Broodmother, Chaos Knight, Nature's Prophet, Phantom Lancer, Terrorblade

Additional:
* Nightmare can easily cleared by Terrorblade's spammable illusions.
* Almost all of Bane's damage revolves exclusively around single-target effects. Terrorblade can almost always get a Sunder off.

* 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.