Meepo
* Each of Meepo's clones count as real heroes, meaning that an Echo Slam hitting them will deal catastrophic damage to Meepo and his team.
* Eathshaker's AoE stuns can interrupt Meepo's 
Poof cast animation.
Additional:
* 
Echo Slam deals catastrophic damage against a cluster of Meepos and anyone nearby.
* He can potentially stunlock any number of Meepos for a fairly long duration, often enough to finish one off.
Naga Siren
* 
Mirror Image's illusions increase Echo Slam's damage.
Additional:
* Earthshaker's strong AoE abilities can clear Naga Siren's illusions, or at least make it easier to distinguish the real one by the damage they take.
* Echo Slam deals more damage against more enemies, which can be devestating against Naga Siren and her illusions.
Meepo
* 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.
Naga Siren
* All of Leshrac's abilities, especially 
Pulse Nova, can easily deal with Naga Siren's illusions.
* 
Aghanim's Scepter gives Leshrac access to 
Nihilism ability, that allows him to turn himself along with Naga Siren and her illusions to turn ethereal. And to make things worse, Nihilism can slow Naga Siren and her illusions, make them more vulnerable to magical damage and unable to fight back while Leshrac moves faster and does not take increased magical damage for it's duration.
Meepo
* Flak Cannon and Call Down will shred Meepo's clones.
* Homing Missile can catch and single out retreating Meepos, making them an easy kill.
Naga Siren
* 
Flak Cannon and 
Call Down can easily clear Naga Siren's illusions.
Meepo
* Because multiple Meepos tend to clump up, they present an easy target for Timbersaw's many area abilities.
* Although be careful since Timbersaw cannot use 
Timber Chain to escape if rooted from 
Earthbind.
Naga Siren
* Timbersaw's innate durability is very hard to deal with as Naga Siren as she mostly relies on sustained damage rather than burst damage unless if she is played as Nuker. Timbersaw's high Pure Damage and low-cooldown AoE nukes can also destroy Naga Siren's illusions very fast. Timbersaw can also build 
Lotus Orb to reflect 
Ensnare back at Naga SIren.
Meepo
* Flaming Lasso is the perfect tool to isolate a single Meepo and focus him.
Naga Siren
* Many stacks of 
Sticky Napalm, combined with 
Flamebreak and 
Firefly, allows Batrider to destroy illusions from Mirror Image.
* If Batrider can manage to destroy all illusions from Naga Siren, he will be able to use 
Flaming Lasso on the real one, and will be able to drag her toward his team, potentially preventing Naga Siren from escaping with 
Song of the Siren.
Additional:
* Many stacks of Sticky Napalm, combined with Flamebreak and Firefly, allows Batrider to destroy illusions from Mirror Image.
* If Batrider can manage to destroy all illusions from Naga Siren, he will be able to use Flaming Lasso on the real one, and will be able to drag her toward his team, potentially preventing Naga Siren from escaping with Song of the Siren.
Meepo
* Meepo lacks the disengages to escape a well-timed Echo Stomp, in particular if Elder Titan is his current target.
* Clones are counted as heroes, increasing massively the power of 
Astral Spirit's buffs, including Aghanim's Scepter's spell immunity buff.
* Meepo relies heavily on high agility and his mediocre strength gain makes him a very prized target for Natural Order.
* Meepo and his clones like to group up to hunt and kill in teamfights or ganks and can be easily disabled together with Echo Stomp.
Additional:
* 
Echo Stomp can completely disable multiple Meepos for 5 seconds.
* Astral Spirit will affect Meepo clones, as they don’t count as illusions. Elder Titan can receive a massive amount of damage, armor and movement speed from each Meepo.
* With 
Natural Order, Elder Titan’s mere existence causes Meepo to be disadvantaged, due to the aura that completely negates his base armor and magic resistance. Combining Astral Spirit with Natural Order allows Elder Titan to easily kill any Meepo within a second, depending on how much damage he gains from Astral Spirit.
* 
Earth Splitter deals over 30%/40%/50% of each Meepo’s max hp, and is even stronger if the Meepos are near Elder Titan due to Natural Order.
Naga Siren
* Heroes with AoE nukes will clear her illusions in no time, especially if they are percentage-damage-based, like 
Underlord's 
Firestorm, 
Elder Titan's Earth Splitter, 
Enigma's 
Midnight Pulse, 
Zeus's 
Arc Lightning, 
Jakiro's 
Liquid Frost from 
Aghanim's Shard etc.
Meepo
* Dark Seer can take great advantage of 
Divided We Stand by putting an Ion Shell on a clone in order to harass them effectively.
* Vacuum can take a single Meepo and disable him for Dark Seer and his teammates to take out.
Naga Siren
* Heroes that rely on illusions typically spawn very strong illusions inside Dark Seer Wall of Replica that he can use against them or their team: 
Phantom Lancer, 
Chaos Knight, 
Naga Siren, 
Terrorblade.
Meepo
* Melee heroes who rely on summons, illusions, or clones will trigger Counter Helix more often, thus taking more damage: 
Meepo, 
Lycan, Phantom Lancer
Additional:
* The combination of 
Counter Helix and 
Berserker's Call can disable multiple Meepos and deal heavy area damage.
* Axe's natural high survivability makes it difficult to burst him down with Poof or chip away at his health with Ransack.
Naga Siren
* Axe will destroy her illusions by proccing Counter Helix more often due to him being hit by more attacks.
Meepo
* Every Meepo clone adds to Thirst's bonuses.
* Bloodseeker can chase down retreating clones when Meepo tries to cycle weaker clones away from combat.
Naga Siren
* Heroes with long-lasting, undispellable debuffs will pinpoint the true Naga Siren: 
Spirit Breaker, 
Bloodseeker, 
Witch Doctor.
Meepo
* Light Strike Array catches Meepo and his clones if he tried to gank Lina with Earthbind & Poof.
* Laguna Blade can quickly kill Meepo and his clones before they escape with Poof.
Naga Siren
* Since Naga Siren is a hero who barely goes for 
Black King Bar, she is vulnerable to nukers with strong magical damage and big area-of-effect spells in every game more than any other carry heroes: 
Sand King, Jakiro, 
Leshrac, 
Lina, 
Earthshaker, Zeus.
Meepo
* 
Focus Fire can quickly attack target Meepo or clones instanly. Additionally, Windranger's can use combinated 
Shackleshot and Focus Fire since Poof wrong landing and stunned from Shackleshot affected Meepo and clones collateral damege from Focus Fire
* Escaping from 
Windrun make Earthbind roots can not reach.
Naga Siren
* As long as Windranger is able to identify the real hero among the illusions, heroes relying on them can be easily tagged with Focus Fire: Chaos Knight, Terrorblade, Phantom Lancer, Naga Siren.
Meepo
* If Meepo ganks Lion with Poof and Earthbind, he will be an easy target for 
Earth Spike & AoE 
Hex from his level 25 talent.
Naga Siren
* 
Lion may upgrade 
Mana Drain, Hex and 
Finger of Death through Talent Tree and Aghanim's itens to make them affect secondary targets or turn them into AoE abilities. This can make things difficult for heroes like Phantom Lancer, Naga Siren and Terrorblade, who rely on illusion armies.
Additional:
* Both Hex and Mana Drain destroy Naga Siren's illusions in an instant, making it hard for her to teamfight or push against a team with Lion. If Lion chooses the AoE effect talent for Hex or the shard for multi-target Mana Drain, it can negate her pushing potential entirely.
* Earth Spike is an AoE disable with good damage. If used well, it can help distinguish the true Naga Siren by the damage they take (illusions take more damage).
Meepo
* 
Great Cleave and 
God's Strength can take down Meepo and his clones very quickly.
* The lack of spell immunity for Meepo's clones makes them vulnerable to 
Storm Hammer.
Additional:
* Great Cleave will devastate Meepo's clones. Against a closely packed group, Sven does not even need to target the clone with the lowest health.
Naga Siren
* Heroes whose attacks can affect multiple enemies at once will clear Naga Siren's illusions. Such heroes include 
Sven, 
Magnus, 
Dragon Knight, 
Luna, 
Medusa, 
Templar Assassin, 
Gyrocopter, 
Muerta.
Meepo
* 
Tiny's Avalanche affects all Meepos and Toss can send a singular Meepo into death.
Additional:
* Avalanche and Toss prevents Meepo's from using Poof to escape.
* Tiny doesn't need to target the weakest clone while he is affected by Tree Grab.
Naga Siren
* Avalanche and Toss combo makes short work of Mirror Image's illusions.
* Tiny's cleave with Tree Grab and area of effect damage with Tree Volley will easily wipe out illusions.
Meepo
* Poof won't damage Medusa and she can use Stone Gaze to disable all of Meepo's clones.
* Mystic Snake will easily become the bane of Meepo early game.
Naga Siren
* Medusa's 
Split Shot and 
Mystic Snake combined with 
Mjollnir, a common item for Medusa, will whittle down all of Naga Siren's illusions, including Naga Siren herself.
* Medusa's 
Stone Gaze can disable Naga Siren even for the duration of Song of the Siren and even if Naga Siren is spell immune, discouraging Naga Siren from even trying to use Song of the Siren to save herself or counter-initiate against Medusa.
Additional:
* Medusa's Split Shot and Mystic Snake combined with Mjollnir, a common item for Medusa, will whittle down all of Naga Siren's illusions, including Naga Siren herself.
* Medusa's Stone Gaze can disable Naga Siren even for the duration of Song of the Siren and even if Naga Siren is spell immune, discouraging Naga Siren from even trying to use Song of the Siren to save herself or counter-initiate against Medusa.
Naga Siren
* 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.
Meepo
* Heroes with powerful area-of-effect disables can initiate on Meepo and his clones and shut him down, such as Enigma, 
Invoker, Magnus, 
Puck, and Sand King.
Additional:
* Burrowstrike can stun multiple Meepos, making them vulnerable targets.
* Epicenter and Sand Storm's AoE damage ensures all Meepo clones get damaged, making it hard for Meepo to choose which one to flee as all are taking damage at the same rate.
* Just be aware when using Sand Storm to escape, as Meepo has good AoE damage and disables, which, as explained in the "Bad Against" section, works well against an invisible Sand King.
Naga Siren
* Since Naga Siren is a hero who barely goes for Black King Bar, she is vulnerable to nukers with strong magical damage and big area-of-effect spells in every game more than any other carry heroes: Sand King, Jakiro, Leshrac, Lina, Earthshaker, Zeus.
Meepo
* Heroes that have doubles or clones such as 
Arc Warden, Meepo or 
Lone Druid are vulnerable to Muerta's 
Gunslinger.
Naga Siren
* Heroes whose attacks can affect multiple enemies at once will clear Naga Siren's illusions. Such heroes include Sven, Magnus, Dragon Knight, Luna, Medusa, Templar Assassin, Gyrocopter, Muerta.
Meepo
* In general, melee heroes without blink mechanisms or spell immunity will have a hard time positioning against Pit of Malice: Sven, Tiny, 
Wraith King, Dragon Knight, Meepo, 
Doom, 
Bounty Hunter, 
Dark Seer, 
Undying, 
Alchemist, 
Legion Commander.
Naga Siren
* Heroes with AoE nukes will clear her illusions in no time, especially if they are percentage-damage-based, like Underlord's Firestorm, Elder Titan's Earth Splitter, Enigma's Midnight Pulse, Zeus's Arc Lightning, Jakiro's Liquid Frost from Aghanim's Shard etc.
Meepo
* Heroes with powerful area-of-effect disables can initiate on Meepo and his clones and shut him down, such as Enigma, Invoker, Magnus, Puck, and Sand King.
Naga Siren
* Heroes with AoE nukes will clear her illusions in no time, especially if they are percentage-damage-based, like Underlord's Firestorm, Elder Titan's Earth Splitter, Enigma's Midnight Pulse, Zeus's Arc Lightning, Jakiro's Liquid Frost from Aghanim's Shard etc.
Meepo
* Because only one clone needs to be killed in order to kill Meepo, heroes that excel at singling out enemies can also be a detriment to him, such as 
Batrider, 
Beastmaster, 
Pudge and 
Clockwerk.
Naga Siren
* Heroes with long cast animations can be continuously interrupted by Battery Assault: 
Centaur Warrunner, Jakiro, Leshrac, Naga Siren, Underlord.
Meepo
* X Marks the Spot is good to prevent a single meepo from escaping from a deadly situation.
* Tidebringer, Torrent and Ghostship destroys Meepo's clones.
Additional:
* 
Tidebringer's cleave damage can wear down Meepo's clones quickly. It can also give Meepo problems in the lane, due to his melee range and initially low health pool.
* 
Ghostship and 
Torrent can effectively disable Meepo while dealing heavy damage.
* 
X Marks the Spot prevents attempts to escape using Poof.
Meepo
* Aggressively Poofing and Earthbinding is not going to end well against Venomancer, as he will be an easy target for 
Poison Nova.
* Venomancer's constant slows greatly reduce Meepo's mobility.
Naga Siren
* 
Arcane Orb deals pure damage that can bypass Naga Siren's armor, and which can clear her illusions in no time.
* 
Astral Imprisonment can be used to prevent Naga Siren from escaping with Song of the Siren. Outworld Destroyer can also use Astral Imprisonment to protect himself from Naga Siren.
* 
Sanity's Eclipse will most likely instantly kill Naga Siren along with her illusions.
Meepo
* 
Winter's Curse in late game is pretty much the end for Meepo or any of his nearby allies. Natural counter for Winter's Curse like 
Linken's Sphere or Lotus Orb is meaningless to her if she can land it on one of your clones.
Additional:
* Meepo's clones usually gets grouped in teamfight making any of them ideal target for Winter's Curse, forcing Meepo to literally kill himself. Also, unlike other heroes he cannot protect himself with Linken's Sphere.
* While Meepo's clones are grouped up, Splinter Blast will hit almost every clone, slowing Meepo and making him easier to fight.
Meepo
* Poof combo puts all of the Meepos very close together, making them vulnerable to Frost Blast's AoE slow and multiple bounces from Chain Frost.
Meepo
* Fatal Bonds links the Meepos together, which combined with area of effect damage or Cleave will be devastating.
Meepo
* With Nether Swap, Vengeful Spirit can isolate one of the Meepos, making him an easier kill for the team.
* Her Magic Missile gives her an easy way to cancel Meepo's Poof, preventing isolated Meepos from fleeing.
Meepo
* Quill Spray usually hits Meepo's clones, although Bristleback cannot turn his back when rooted with Earthbind.
Naga Siren
* Dawnbreaker can easily clear waves of Naga Siren's illusions from Mirror Image with 
Starbreaker, 
Celestial Hammer and 
Solar Guardian.
* Aghanim's Shard upgraded Starbreaker will allow Dawnbreaker to dispel Ensnare and freely attack Naga Siren during Song of the Siren when combined with Black King Bar, a common item on Dawnbreaker.
* Solar Guardian allows Dawnbreaker to counter any attempts of Naga Siren and rejoin her team with Solar Guardian when they require it. Aghanim's Scepter upgraded Solar Guardian can also give Dawnbreaker's allies evasion while Dawnbreaker is airborne for it's duration, as Naga Siren mainly relies on direct attacks in order to deal damage.
Additional:
* Dawnbreaker can easily clear waves of Naga Siren's illusions from Mirror Image with Starbreaker, Celestial Hammer and Solar Guardian.
* Aghanim's Shard upgraded Starbreaker will allow Dawnbreaker to dispel Ensnare and freely attack Naga Siren during Song of the Siren when combined with Black King Bar, a common item on Dawnbreaker.
* Solar Guardian allows Dawnbreaker to counter any pushing attempts of Naga Siren and rejoin her team with Solar Guardian when they require it. Aghanim's Scepter upgraded Solar Guardian can also give Dawnbreaker's allies evasion while Dawnbreaker is airborne for it's duration, as Naga Siren mainly relies on direct attacks in order to deal damage. Solar Guardian can also be used after Naga Siren uses Song of the Siren near her allies to either escape from or counter-initiate against them.
Meepo
* Meepo is vulnerable to area damage and disables from Magnus himself as well as his team through Empower.
Naga Siren
* Heroes whose attacks can affect multiple enemies at once will clear Naga Siren's illusions. Such heroes include Sven, Magnus, Dragon Knight, Luna, Medusa, Templar Assassin, Gyrocopter, Muerta.
Naga Siren
* 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.
Meepo
* 
Tree Dance and 
Primal Spring allows him to chase a retreating Meepo.
* 
Boundless Strike gains critical strike bonuses and 
Wukong's Command can take down Meepo and his clones very quickly.
Additional:
* Monkey King can gain 
Jingu Mastery stacks on Meepo’s clones from Divided We Stand.
* Tree Dance allows him to sneak up on and gank a lone Meepo clone.
Meepo
* Casting Bramble Maze on top of Meepo guarantees a root, as it is nearly impossible to leave the thorns with all of Meepo's clones.
* Terrorize and Cursed Crown offer great disables against the grouped Meepos and can prevent them from using Poof to escape.
Meepo
* Meepo is quite fragile in the early game and can be easily taken down by Flame Guard's and Searing Chains' damage. Later on, Meepo is very vulnerable to Sleight of Fist's damage due to 
Battle Fury's cleave on multiple Meepos.
Additional:
* 
Sleight of Fist boosted by Battle Fury and 
Daedalus makes quick work of Meepo if clones are crowded around each other.
* 
Searing Chains interrupts Meepo's initiating because Meepo's clones do not have spell immunity.
Naga Siren
* Heroes that heavily depend on illusions or summons, (Naga Siren, Terrorblade, Phantom Lancer, Lycan,...) are vulnerable to Sleight of Fist and even more so if Ember Spirit has Battle Fury.
Meepo
* Heroes with high mobility can be prevented from using it to their advantage with Earthbind, even if they pack a dangerous arsenal: 
Earth Spirit, 
Ember Spirit, 
Storm Spirit, 
Nature's Prophet, 
Phantom Assassin, Riki, 
Anti-Mage, 
Weaver.
* See items and abilities disabled by roots
Meepo
* 
Bulwark blocks the attack from Meepo and his clones.
* 
Spear of Mars & 
God's Rebuke prevents Meepo and his clones from initiation or escaping.
Naga Siren
* Heroes with long-lasting, undispellable debuffs will pinpoint the true Naga Siren: Spirit Breaker, Bloodseeker, Witch Doctor.
Meepo
* 
Troll Warlord can root and deal a lot of damage to a single Meepo while lifestealing through the assault from the other Meepos. Meepo needs expensive items like 
Ethereal Blade or 
Heaven's Halberd to be able to fight him.
Naga Siren
* Heroes who are reliant on illusions or summons: Chaos Knight, 
Broodmother, Naga Siren.
Naga Siren
* Heroes who are reliant on illusions: Chaos Knight, Phantom Lancer, Naga Siren.
Additional:
* Centaur's 
Retaliate will harm all attacking enemies, which will allow Centaur Warrunner to see which is the real Naga Siren.
* A well timed 
Hoof Stomp followed by 
Double Edge will clear all Naga's illusions and prevent Naga Siren from escaping with Song of the Siren.
Naga Siren
* Illusion heroes will struggle against Primal Beast's area damage capability, such as Chaos Knight, Naga Siren, Terrorblade.
Meepo
* Heroes with powerful area-of-effect disables can initiate on Meepo and his clones and shut him down, such as Enigma, Invoker, Magnus, Puck, and Sand King.
Meepo
* 
Shadow Fiend's Requiem of Souls not only slow all Meepos, but it can also kill the weakest Meepo instantly if the ultimate is released at the right position and time.
Additional:
* Shadow Fiend can easily focus down and kill one of the Meepos.
* The amount of damage from Shadow Fiend's AoE spells makes Meepo vulnerable in every aspect.
Meepo
* Because only one clone needs to be killed in order to kill Meepo, heroes that excel at singling out enemies can also be a detriment to him, such as Batrider, Beastmaster, Pudge and Clockwerk.
Meepo
* Heroes with powerful area-of-effect disables can initiate on Meepo and his clones and shut him down, such as Enigma, Invoker, Magnus, Puck, and Sand King.
Meepo
* Heroes who can stun multiple units at once: 
Dark Willow, Spirit Breaker, 
Slardar, Invoker, and Tidehunter.
Naga Siren
* Heroes whose attacks can affect multiple enemies at once will clear Naga Siren's illusions. Such heroes include Sven, Magnus, Dragon Knight, Luna, Medusa, Templar Assassin, Gyrocopter, Muerta.
Meepo
* Because only one clone needs to be killed in order to kill Meepo, heroes that excel at singling out enemies can also be a detriment to him, such as Batrider, Beastmaster, Pudge and Clockwerk.
Meepo
* Besides Lone Druid and Meepo, Doom is potentially good versus every hero since Doom will render any hero helpless for a prolonged 16 seconds. This is particularly true for fragile heroes that heavily rely on mobility to stay alive.
Meepo
* 
Reactive Tazer can lock multiple Meepos in place and prevent them from Poofing.
* 
Proximity Mines, 
Sticky Bomb and 
Blast Off! can deal heavy magic damage to multiple Meepos.
Naga Siren
* 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.
Naga Siren
* 
Mortimer Kisses can make quick work of Naga Siren's illusions.
* 
Scatterblast and 
Firesnap Cookie's AoE damage are also decent ways to deal with Naga's illusions.
Meepo
* 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.
Meepo
* Pangolier's arsenal deals heavy damage in a wide area, make him deadly even for a Meepo with a high magic resistance.
* 
Shield Crash can easily give him a ridiculous 80% damage resistance (Becomes 100% if Pangolier gets his +5% Shield Crash talent, Or there is 5 Meepos), resulting in a near unkillable Pangolier in a short amount of time.
* 
Rolling Thunder disrupts Meepo's initiation or escaping.
* 
Swashbuckle can hit all of Meepo clones.
* 
Lucky Shot can disarm Meepo's clones.
Additional:
* Shield Crash gains its damage reduction bonus from all Meepo clones, and can be used even when rooted, allowing Pangolier to gain a massive amount of damage reduction (even more than 100%).
* With too many clone running around during combat, it is almost impossible for Meepo to avoid Rolling Thunder or Swashbuckle.
* Still, remember that a lone Pangolier can never escape from a ganking Meepo.
Naga Siren
* Heroes who are illusion based, or even heroes who frequently build Manta Style can be cleared quickly by Pangolier's high damage, or lose their damage ouput because of Lucky Shot: Chaos Knight, Naga Siren
Meepo
* 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
Naga Siren
* 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
Meepo
* Flux is severely impaired against Meepo because of Divided We Stand.
* Meepo's farming speed and early powerspikes allows him to pressure Arc Warden before he is capable of fighting effectively.
* Without Black King Bar, Earthbind and Poof can finish Arc Warden quickly before he has time to do much.
Naga Siren
* 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.
Meepo
* Earthbind, like any root, inhibits usage of 
Ball Lightning, eliminating Storm Spirit's mobility.
Naga Siren
* 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.
Meepo
* Nature's Prophet is heavily countered by Meepo, not only Meepo can kill the treants with a single Poof, but he can also stop Nature's Prophet from using 
Teleportation, and can gain vision inside 
Sprout.
Additional:
* Meepo can net Nature's Prophet's treants with Earthbind and then Poof them, putting an end to his pushing.
* Skilled Meepos can rival and even exceed Nature's Prophet's global presence by combining Poof with 
Boots of Travel, meaning that he can not only stop his push, but also can kill him if he is not careful.
Naga Siren
* 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.
Meepo
* 
Night Stalker's most skills are single targeted which allows other Meepos to Poof, Earthbind and kill him.
Naga Siren
* 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.
Meepo
* Necrophos struggles at clearing away durable illusions or summons. Meepo can overwhelm Necrophos with his many duplicates, especially in the later stages of the game, and his Earthbind will prevent Necrophos from getting away, even if he casts Ghost Shroud.
* Meepo's high burst damage from Poof can make it difficult for to Necrophos to stay alive, and as Necrophos excels in extended fights, he will not be able to do as much damage as he intends to.
Naga Siren
* 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.
Naga Siren
* Heroes who rely on illusions will see them destroyed easily by Overwhelming Odds: Phantom Lancer, Chaos Knight, Terrorblade, Naga Siren
Meepo
* When Legion Commander uses 
Duel on one Meepo, he can use his other Meepos to kill her. If he wasn't dueled, he can help the teammate who was duelled to give the teammate the damage instead of Legion Commander.
* However, if Legion Commander picked up an Aghanim's Scepter and she duels one Meepo, that might be the end of Meepo if Legion managed to gather enough damage from previous duels.
Naga Siren
* Song of the Siren lasts long enough to prevent a successful Duel (but only if Naga wasn't the target).
Naga Siren
* Sand King and Phoenix have many tools to deal with multiple enemies at once, which will work well against a crowd of illusions.
Meepo
* Earthbind can prevent Phoenix from using 
Icarus Dive, the only escaping mechanism of this hero.
* Heavy burst damage from Poof can easily kill Phoenix even when it slows down all the Meepos with 
Fire Spirits.
* Meepo's clones destroy the Phoenix Sun from 
Supernova in no time, even when they are slowed down by Fire Spirits.
* Meepo's naturally high magic resistance gives Phoenix a hard time with bursting him down. He can even turn the tide if Icarus Dive is on cooldown.
Additional:
* Meepo is unlike any other multi-unit enemy Phoenix may face in the battlefield. Unlike illusion-based heroes like Phantom Lancer or Chaos Knight, Meepo's clones are not illusions, meaning they can deal full damage to the Phoenix Sun if all four (or five) are present.
Naga Siren
* 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.
Meepo
* Slark's Dark Pact and Pounce can deny only one Earthbind and Poof can penetrate Shadow Dance if he doesn't build Black King Bar.
Additional:
* Earthbind and Poof will still hit Slark in Shadow Dance.
* Dark Pact can only remove one Earthbind.
* 
Ransack will still affect Slark, even if he has a Black King Bar.
Naga Siren
* 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.
Meepo
* Heroes with high mobility can be prevented from using it to their advantage with Earthbind, even if they pack a dangerous arsenal: Earth Spirit, Ember Spirit, Storm Spirit, Nature's Prophet, Phantom Assassin, Riki, Anti-Mage, Weaver.
* See items and abilities disabled by roots
Additional:
* Root is a deadly threat to Riki, disabling both 
Blink Strike and 
Tricks of the Trade while making him fully revealed, making Earthbind a good ability against him.
* 
Smoke Screen may not be able to silence all the Meepo clones.
* Riki has no true area damage, as Tricks of the Trade's damage is distributed between all Meepo clones, so he cannot effectively fight Meepo or deal with his strong ability to push unless Riki has Battle Fury.
Naga Siren
* 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.
Meepo
* 
Tinker who can't fight multiple heroes will suffer greatly against Ransack and Earthbind.
Naga Siren
* 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.
Meepo
* Meepo has a better advantage in farm with Divided We Stand, as well as having a higher attack speed due to his tendency to build items that give attributes. In addition, Wraithfire Blast stuns only one target, and choosing to engage one Meepo will most certainly mean engaging them all.
Naga Siren
* 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.
Naga Siren
* 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 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.
Naga Siren
* 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.
Naga Siren
* 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.
* 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.
Naga Siren
* Ensnare with her attacks allows Naga Siren to gank Sniper easily.
* Rip Tide removes Sniper's very little armor.
Meepo
* Poof will destroy Shadow Demon's illusions created by 
Disruption and quickly escapes from 
Shadow Poison & 
Demonic Purge.
Naga Siren
* Heroes whose attacks can affect multiple enemies at once will clear Naga Siren's illusions. Such heroes include Sven, Magnus, Dragon Knight, Luna, Medusa, Templar Assassin, Gyrocopter, Muerta.
Meepo
* Multiple attackers thanks to summoned units or clones: Meepo, Witch Doctor, Lycan, Enigma, Shadow Shaman
* 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), Jakiro, Pugna, Doom
Naga Siren
* Ensnare disables Templar Assassin's invisibility and Blink Dagger (a core item on Templar Assassin), and her illusions will break 
Refraction easily.
Meepo
* Chain of Earthbinds prevents her from using Blink, allowing Meepo to quickly kill her with Poof and attacks.
* Meepo tends to buy items with attributes, mitigating Queen of Pain's magical burst.
Additional:
* Meepo is the hard counter for Queen of Pain - chaining Earthbinds prevents her from using Blink for a long time, and without any other escape options, Queen of Pain cannot survive several Poofs and attacks.
* Meepo tends to build items with attributes, mitigating Queen of Pain's magical burst.
Naga Siren
* 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.
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.
Meepo
* Ogre Magi has single-targeted magical-only damage and disables and is less effective against Meepo's clones.
Naga Siren
* 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.
Meepo
* Earthbind prevents Broodmother from escaping Meepo's attacks.
* Poof will quickly clear any nearby spiders.
* Broodmother often picks off single target heroes. With Meepo's Divided We Stand, it gets a lot harder once every Meepo Poofs in.
Meepo
* With all 5 Meepos available, all of Shaman's wards will be disposed of very quickly.
* All of Shaman's disables are based around single target control, and he can at most only disable two Meepos, allowing the rest to easily lay waste to him, be it during the channel duration of Shackles or by using Earthbind.
Meepo
* Multiple Earthbinds allows Meepo to lock down Anti-Mage almost indefinitely.
* Meepo's clones can only use their mana for Poof, keeping their mana pool nearly full and thus making them a bad target for a Mana Void.
Additional:
* Earthbind can prevent Anti-Mage from using 
Blink, allowing Meepo to kill him with attacks and Ransack.
Meepo
* Poof will destroy Phantom Lancer's illusions within a short time.
* Earthbind prevents Phantom Lancer from using 
Doppelganger.
Additional:
* Poof from multiple Meepos will destroy illusions quickly.
* Earthbind's area root can catch Phantom Lancer in a group of illusions and prevent him from using Doppelganger for a long time.
* Meepo aims to end the game as early as possible, while Phantom Lancer is a lategame hero.
* This also means that, in the late game, Meepo stands no chance against Phantom Lancer.
Naga Siren
* 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.
Naga Siren
* 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.
Naga Siren
* 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.
Meepo
* Heroes who can stun multiple units at once: Dark Willow, Spirit Breaker, Slardar, Invoker, and Tidehunter.
Meepo
* Slardar does not do well against multiple targets, as his only way to damage multiple targets is Slithereen Crush.
* Meepo's Earthbind will root Slardar, making him unable to chase/escape for the time being. Also, Poof's low cooldown and high damage can burst Slardar down rather quickly.
Naga Siren
* 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.
Naga Siren
* 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.
Naga Siren
* 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
Meepo
* 
Mirana cannot use Leap while rooted by Earthbind and her Moonlight Shadow is countered by Meepo's true sight that is provided by Earthbind.
Additional:
* Earthbind prevents Mirana from Leaping or going invisible with Moonlight Shadow. She can be easily killed by Poof and Ransack while disabled.
* Landing a Sacred Arrow on Meepo does not render him helpless, as all of the other Meepos can still fight back.
Meepo
* Heroes with high mobility can be prevented from using it to their advantage with Earthbind, even if they pack a dangerous arsenal: Earth Spirit, Ember Spirit, Storm Spirit, Nature's Prophet, Phantom Assassin, Riki, Anti-Mage, Weaver.
* See items and abilities disabled by roots
Meepo
* Heroes with high mobility can be prevented from using it to their advantage with Earthbind, even if they pack a dangerous arsenal: Earth Spirit, Ember Spirit, Storm Spirit, Nature's Prophet, Phantom Assassin, Riki, Anti-Mage, Weaver.
* See items and abilities disabled by roots
Meepo
* 
Skywrath Mage's abilities are single targeted and he can't use Mystic Flare to its fullest potential, since all Meepos spread the damage between them. He also has no disables to prevent Meepo from Poofing to another one (unless he can get 
Ancient Seal off first).
Naga Siren
* 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.
Meepo
* Meepo can quickly destroy Tombstone thanks to Divided We Stand.
Naga Siren
* 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.
Meepo
* Pugna's Nether Ward doesn't really hurt Meepo since he usually buys attribute items to tank up and can be killed very quickly by 4 clones. Decrepify can amplify Poof's damage should Pugna use it to avoid Meepo's right clicking.
Meepo
* Lifestealer is not affected by Earthbind or Poof during Rage, making him a difficult target to work around.
Meepo
* Lifestealer's Rage and Open wounds become useless when Meepo has 4 or more clones, as Ransack will heal Meepo too quickly for Lifestealer to take down.
Naga Siren
* Heroes with illusions: Chaos Knight, Naga Siren, Phantom Lancer, Terrorblade
Naga Siren
* 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.
Meepo
* Spectre's Haunt with Radiance may be useful for countering Meepo but if Meepo finds the real one, Spectral Dagger is useless. Non-Black King Bar heroes like her will suffer from all of Meepo's abilities. Meepo is also a very large counter as Spectre takes a long time to come online, normally farming in the jungle or in lane, which makes her an easy target for Meepo ganks.
Additional:
* Poof combined with Earthbind can be used to easily lockdown and burst Spectre down.
* As Meepo's playstyle is often to come online early to mid game and take over the whole game, Meepo will often be much further ahead of Spectre in farming.
* Meepo's global map presence allows him to effectively hunt for Spectre and disrupt her farm.
* Spectre has no strong AOE abilities or way to control or lock down Meepo.
Naga Siren
* Illusion-based and multi-unit heroes can take advantage of Chaos Knight's lack of area damage: Naga Siren, Phantom Lancer, Broodmother
Meepo
* Heroes that can overwhelm Visage by sheer number like Chaos Knight, Meepo, Terrorblade and Phantom Lancer.
Meepo
* 
Enchantress's 
Untouchable slows down Meepos attacks and 
Impetus can deal heavy pure damage to a single Meepo, however once Meepo has closed the gap she is an easy target for Poof.
Meepo
* Meepo can quickly kill Enchantress with a Poof combo, rendering Untouchable useless.
Meepo
* 
Void Spirit can dodge Earthbind with 
Dissimilate and 
Astral Step, giving him a good chance to escape. If he gets caught anyways, 
Resonant Pulse allows him to retaliate.
Meepo
* Meepo's Earthbind can easily lockdown Void Spirit.
* Meepo and his clones can easily burst Void Spirit's Resonant Pulse.
Meepo
* Heroes who can stun multiple units at once: Dark Willow, Spirit Breaker, Slardar, Invoker, and Tidehunter.
Naga Siren
* Heroes with long-lasting, undispellable debuffs will pinpoint the true Naga Siren: Spirit Breaker, Bloodseeker, Witch Doctor.
Meepo
* Earthbind's root prevents/interrupts Charge of Darkness.
* As a single-target focused hero without much damage output, Spirit Breaker is ineffective in general against Meepo.
Naga Siren
* 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.
Meepo
* 
Phantom Strike allows Phantom Assassin to jump on his clones.
* Meepo's low health pool can burst down by 
Coup de Grace critical strike.
Meepo
* Heroes with high mobility can be prevented from using it to their advantage with Earthbind, even if they pack a dangerous arsenal: Earth Spirit, Ember Spirit, Storm Spirit, Nature's Prophet, Phantom Assassin, Riki, Anti-Mage, Weaver.
* See items and abilities disabled by roots
Naga Siren
* 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.
Naga Siren
* Blade Fury offers good AoE damage to clear illusions and can hurt the real Naga Siren as well if she chooses to blend in the illusions. Diffusal Blade does nothing to Juggernaut either when he uses Blade Fury.
* Aghanim's Shard upgraded Blade Fury along with Lv 20 DPS talent will shred all illusions almost instantly, especially when combined with Mjollnir, a common item for Juggernaut.
Meepo
* Juggernaut's Omnislash is meaningless for Meepo who can share the damage across clones to save other allies.
Naga Siren
* Illusion-based heroes are effective against Omnislash and Juggernaut's single-targeted damage: Naga Siren, Chaos Knight, Terrorblade,Phantom Lancer.
Naga Siren
* 
Waveform clear Mirror Image illusions from Naga Siren. And though Ensnare can prevent Morphling from using Waveform to escape, he can easily dispel it with Manta Style, a common item on Morphling.
* 
Morph allows Morphling to copy Naga Siren's abilities and combine them with Manta Style, a commong item for Morphling, to destroy Naga Siren's illusions. Aghanim's Scepter upgraded Morph also allows Morphling to create a strong illusion of Naga Siren that can do the same and which can also allow Morphling to close the gap on Naga Siren.
Meepo
* Earthbind disables Waveform, effectively keeping Morphling in place for an extended period of time, allowing Meepo to deal considerable damage with Poof.
Naga Siren
* Keeper of the Light can stall pushes with 
Illuminate. This makes him strong against pushing heroes: Terrorblade Naga siren Nature's Prophet and Anti-Mage
Meepo
* Heroes that can jump and kill him: Meepo, 
Clinkz, Templar Assassin
Meepo
* 
Nethertoxin prevents the lifesteal from Ransack.
* Meepo and his clones have a lack of magic resistance, so they're vulnerable to 
Poison Attack & 
Viper Strike directed onto one clone.
Naga Siren
* 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.
Naga Siren
* Dazzle can instantly destroy all of Naga Siren's illusions from Mirror Image with Aghanim's Shard upgraded 
Poison Touch used on her or any of her illusions.
Naga Siren
* 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.
Meepo
* Illusions and summons are double-edge sword type of matchup for Luna. On one hand, they can tank damage from Eclipse, but on the other hand, she can easily clear them before Eclipse with Moon Glaives. Examples include 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).
Naga Siren
* Luna's 
Moon Glaives and 
Lunar Blessing can clear waves of Naga Siren's illusions from Mirror Image.
* Once Naga Siren's illusions are cleared with Aghanim's Shard upgraded Moon Glaives, 
Eclipse can often finish off Naga Siren before she can escape with Song of the Siren.
* A well-timed Aghanim's Scepter upgraded Eclipse combined with 0.25 Eclipse Lucent Ministun talent can be casted at long range and allow Luna to burst down Naga Siren faster and repetively stun Naga Siren, preventing her from escaping with Song of the Siren and 
Town Portal Scroll without getting caught in it's range.
* Luna is a natural Black King Bar wielder unlike Naga Siren who barely goes for it, which allows Luna to freely attack Naga Siren during Song of the Siren and potentially get rid of the most of the damage and crowd-control from Naga Siren.
Additional:
* Luna's Moon Glaives and Lunar Blessing can clear waves of Naga Siren's illusions from Mirror Image.
* Once Naga Siren's illusions are cleared, Eclipse can often finish off Naga Siren before she can escape with Song of the Siren.
* A well-timed Aghanim's Scepter upgraded Eclipse combined with 0.25 Eclipse Lucent Ministun talent can be casted at long range and allow Luna to burst down Naga Siren faster and repetively stun Naga Siren, preventing her from escaping with Song of the Siren and Town Portal Scroll without getting caught in it's range.
* Luna is a natural Black King Bar wielder unlike Naga Siren who barely goes for it, which allows Luna to freely attack Naga Siren during Song of the Siren and potentially get rid of the most of the damage and crowd-control from Naga Siren.
Meepo
* Even though Moon Glaives can bounce between Meepo and his clones, Meepo can tank Eclipse because of his clones.
* Earthbind takes away Luna's mobility advantage.
* Meepo can shutdown Luna's split-push ability with his global presence.
* For the same reasons, Meepo makes a very powerful ally for Luna when they are in the same team.
Naga Siren
* 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.
Meepo
* Low-health, normally mobile carries with a lot of damage are vulnerable to Bane's nukes and disables: Anti-Mage, Clinkz, 
Drow Ranger, Faceless Void, Gyrocopter, Juggernaut, Luna, Meepo, Mirana, 
Monkey King, 
Morphling, Phantom Assassin, Phantom Lancer, Riki, Shadow Fiend, Slark, 
Sniper, Terrorblade, Troll Warlord, Weaver.
Naga Siren
* Heroes with illusions and summons can swarm Bane, who has no area abilities outside from Aghanim's Shard upgraded 
Brain Sap: Broodmother, Chaos Knight, Naga Siren, Nature's Prophet, Phantom Lancer, Terrorblade, Visage, Warlock, Wraith King.
Meepo
* Tether helps Io escape from Earthbind even if Meepo has Blink Dagger.
* Io's Spirits can pressure Meepo while laning and will usually hit at least one of his clones.
Naga Siren
* 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.
* 
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.
Naga Siren
* Zeus's abilities deal high amounts of burst magical damage, which ignores Naga Siren's high armor.
* Arc Lightning is a good way to destroy Naga Siren's illusions due to it's capabilities to bounce between enemies.
* 
Static Field from Aghanim's Shard can automatically hit everything in a big radius, taking a huge chunk of health out of Naga Siren's illusions, regardless of how much health they have.
Meepo
* Thundergod's Wrath strikes only the first Meepo.
* Zeus has low mobilty so consecutive Earthbinds are easy to hit and he'll quickly die from Poofs.
Meepo
* All of Jakiro's skills are Area of Effect, which can easily affect all Meepos in a targeted area.
Naga Siren
* Jakiro's damage over time abilities can clear Naga Siren's illusions and can hurt real Naga Siren even for the duration of
Song of the Siren.
Black King Bar, and that makes her very vulnerable to Jakiro's damage over time in every phase of the game.
Song of the Siren.
Black King Bar, this can make her very vulnerable to Jakiro's damage over time in every phase of the game.
* Naga Siren is not a hero that likes to go for
Additional:
* Jakiro's damage over time abilities can clear Naga Siren's illusions and can hurt real Naga Siren even for the duration of
* Since Naga Siren is a hero who barely goes for