* Dark Pact is minimally effective against Phantasm illusions, and Slark lacks area damage otherwise.
* Pounce can be counteracted by Reality Rift.
* Slark is naturally frail and dies quickly to Chaos Knight's burst damage before he can build Essence Shift stacks.
* Be aware, however, that Shadow Dance can make Slark hard to kill as he can't be targeted during its duration.
Additional:
* Phantasms have enough health to survive Dark Pact, and Slark has no other source of AoE damage to deal with them.

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

* Jakiro's damage over time force Chen to use Hand of God prematurely, potentially wasting chance to save his allies during teamfight.
* Macropyre can also disrupt Chen's jungling work.
Additional:
* Liquid Fire and Dual Breath can clear Chen's creeps, and kill his allies before he uses Hand of God.
* Macropyre can quickly clear Chen's creeps and deal intense damage to his allies.

* 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.

* All of Jakiro's active skills can be targeted on an area, which is effective at forcing Templar Assassin to move should she Meld away.
* Many of Jakiro's spells utilize damage-over-time mechanics, which makes it easy to strip away layers of Refraction.

* 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

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

* Heroes with damage over time abilities can quickly eat through Gravekeeper's Cloak charges like Huskar, Jakiro and Queen of Pain.

* Jakiro's Macropyre can help him to escape from Sprout and can disrupt Nature's Prophet's jungling.
* Jakiro can disrupt Nature's Prophet's escape attempt with Teleportation with Ice Path.
Additional:
* Jakiro's skill arsenal can ruin Nature's Prophet's gameplay: Dual Breath and Liquid Fire can clear treants from Nature's Call while simultaneously slowing Nature's Prophet, Ice Path can disrupt Nature's Prophet's escaping attempt with Teleportation and Macropyre can not only clear treants from Nature's Call, but also can free Jakiro from Sprout.

* Phantasm's illusions make it difficult to land Meat Hook and Dismember.
* Chaos Bolt is a comparatively low cooldown tool to interrupt Dismember.
* Chaos Strike's lifesteal offsets Rot's damage.

* Phantasm's illusions can be used to push towers and force Techies to detonate Remote Mines.
* Phantasm's illusions can be used to sweep Proximity Mines and Stasis Traps.
* Chaos Knight can easily kill a lone Techies before they Blast Off!.

* Chaos Knight's tanky illusions easily take advantage of Troll Warlord's lack of AoE damage.
* Chaos Bolt can stun Troll for up to 4 seconds and Reality Rift prevents Troll Warlord from chasing down foes.
* Phantasm increases Chaos Knight's physical damage output up to 4 times and can easily kill Troll Warlord before he has a chance to use Battle Trance or a Black King Bar.

* Razor has no way to deal with Chaos Knight's multiple illusions from Phantasm.

* Viper has no response to the standard initiation combo of Reality Rift into Chaos Bolt.
* Phantasm can eliminate Viper almost instantly with its damage output.
Additional:
* As Viper focuses on single-target damage, he has trouble fighting off Phantasm illusions.
* Reality Rift counteracts Viper's slows and reduces his durability.

* Reality Rift lets Chaos Knight bypass the Spirit Bear and jump onto Lone Druid.
* The Spirit Bear's lack of scaling means it dies quickly to Chaos Knight during the late-game.

* Phantasm dispels Track, and the illusions make it difficult to Track the real Chaos Knight.
* Bounty Hunter is fragile and can easily be killed by Chaos Knight and Phantasm's illusions.

* Phantasm dispels Ignite and makes targeting the real Chaos Knight much harder.

* Innately fragile heroes will die almost instantly to Reality Rift while Chaos Knight has illusions active: Drow Ranger, Bane, Necrophos, Crystal Maiden.

* Ice Path allows Jakiro to easily cancel Freezing Field.
* Freezing Field makes Crystal Maiden an easy target for all of his abilities without a Black King Bar.
* With the talent for Macropyre dealing Pure Damage and ignoring spell immunity, Black King Bar becomes nearly useless for Crystal Maiden, as its high damage over time and long duration will force Crystal Maiden to forcefully cancel Freezing Field.

* With Dual Breath, Liquid Fire and Macropyre Jakiro can quickly remove all Living Armor from a target.
* Ice Path allows Jakiro to prevent Treant Protector from using Overgrowth while staying at a safe distance.

* Wraith King has no form of AoE to clear Chaos Knight's illusions from Phantasm.
* Wraith King is very vulnerable if he reincarnates in the middle of his illusions.

* Reality Rift pulls out Night Stalker while he tries to escape or chase.
* Night Stalker doesn't have a lot of ways to deal with multiple targets, which makes him vulnerable to Phantasm illusions from early to mid game, until Night Stalker buys Aghanim's Scepter.

* Chaos Knight can dispel Flux with Phantasm.
* Chaos Knight can use Reality Rift to pull Arc Warden out of Magnetic Field.
* Once Chaos Knight jumps on Arc Warden with Reality Rift, Arc Warden struggles to escape due to low mobility.

* Chaos Knight's high health pool makes him resistant to Zeus' burst damage. Phantasm can dispel Veil of Discord, a typical item purchased by Zeus.
* Zeus is easily overwhelmed by Chaos Knight's strong illusions, as Arc Lightning is not enough to kill them fast enough to have any impact.
* Zeus' low base armor makes him extremely vulnerable to Chaos Knight's high damage output and armor reduction.

* Riki can easily be caught in an Ice Path and Macropyre combo as he finishes Tricks of the Trade.

* Reality Rift will disable Drow Ranger's Marksmanship, along with Chaos Bolt he can keep her locked for enough time to be killed.
* Phantasm's illusions are hard for Drow Ranger to deal with as she lacks of AoE damage.

* Chaos Knight, Lone Druid, Meepo and Arc Warden can be hard targets since Shadow Demon's spells are ill-suited to fight many enemies at once.

* Jakiro's early pushing ability from Liquid Fire makes Jakiro very strong against heroes, that take a long time to get online: Morphling, Naga Siren, Spectre.

* Ursa struggles against illusion heroes like Chaos Knight and Phantom Lancer.

Additional:
* Ursa cannot effectively fight against Phantasm's illusions with his single-target damage.
* Chaos Bolt's potentially long stun with Chaos Bolt gives Ursa little opportunity to Enrage.

* Single-target disablers will have difficulty locking down a Chaos Knight with Phantasm active: Bane, Beastmaster, Bloodseeker, Clockwerk, Doom, Shadow Shaman.

* Chaos Knight with Phantasm
* 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

Additional:
* Phantasm removes Glimpse and dispels Thunder Strike. Additionally, the Phantasm illusions make it difficult to use Glimpse and Thunder Strike on the real Chaos Knight.
* Disruptor's lack of mobility, combined with his lack of innate defense, sets him up for a Reality Rift and a beatdown by Chaos Knight and his illusions.

* Single-target disablers will have difficulty locking down a Chaos Knight with Phantasm active: Bane, Beastmaster, Bloodseeker, Clockwerk, Doom, Shadow Shaman.

* 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 illusions can overwhelm Huskar, as he has no AoE abilities: Phantom Lancer, Anti-Mage, Arc Warden, Chaos Knight.

* Single-target disablers will have difficulty locking down a Chaos Knight with Phantasm active: Bane, Beastmaster, Bloodseeker, Clockwerk, Doom, Shadow Shaman.

* Chaos Knight's multiple illusions from Phantasm can destroy Undying, as Soul Rip can't offset the damage from the high amount of damage from his illusions.

* Warlock is a very strong hero when positioned correctly, and his long cast range helps him with this. However, some Heroes might disrupt or sneakily pass through your allies and deal with you, preventing you from doing your job. Such heroes include Chaos Knight, Spirit Breaker, Riki, and some others.

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

Additional:
* Phantasm's illusions make it difficult for Bane to target Chaos Knight with Nightmare, Brain Sap and Fiend's Grip.
* Chaos Bolt is a comparatively low cooldown tool to interrupt Fiend's Grip.
* Nightmare can be transferred by Phantasm illusions.

* Jakiro's early pushing ability from Liquid Fire makes Jakiro very strong against heroes, that take a long time to get online: Morphling, Naga Siren, Spectre.

* Heroes who relies on illusions and summons (Beastmaster, Chaos Knight, etc.).

* All of Jakiro's skills are Area of Effect, which can easily affect all Meepos in a targeted area.

* While Blade Fury is on cooldown, Juggernaut can easily killed by a standard Chaos Bolt & Reality Rift combo.
* Phantasm illusions can tank Omnislash.

* Broodmother and her Spiderlings need to be very careful during the laning stage against Jakiro, as Jakiro can take down Broodmother's Spiderlings, preventing her from pushing.

* Jakiro has 3 damage over time spells, 2 of which are from debuffs on Puck (Dual Breath and Liquid Fire) and 1 affecting an entire area (Macropyre), making it easy for him to disable the blink dagger.
* Ice Path is also strong against Puck, as he can cast it towards Puck during Phase Shift, who then gets instantly stunned once Phase Shift ends.

* Chaos Knight's Level 20 Talent: Reality Rift Pierces Spell Immunity allows for quick bursting down of Lifestealer during his Rage.
* Phantasm dispels Open Wounds.
* Lifestealer has no way of dealing with Chaos Knight's illusions.

* Dual Breath slows down Phantom Lancer and his illusions.
* Liquid Fire will not only deal AoE damage but also lowers Phantom Lancer's attack speed.
* An Ice Path and Macropyre combo can easily clear all of Phantom Lancer's illusions.
Additional:
* Jakiro's spells inflict AoE damage, meaning he can take down Phantom Lancer's illusion army very quickly.

* While Chaos Knight can land far away from Rubick due to Telekinesis, it can be counteracted by Reality Rift.
* Phantasm dispels Fade Bolt's damage reduction debuff.
* Rubick is fragile and can easily be killed by Chaos Knight and Phantasm's illusions, before he retaliates.

* Heroes with illusions and summons can be hard for Phantom Assassin to deal with, as she lacks any AoE abilities to deal with them: Broodmother, Phantom Lancer, Chaos Knight.

* Casting Phantasm before a fight minimizes the disruption from Global Silence.
* Because Chaos Knight generally relies on attack damage, Silencer's spells won't be as effective against him.

* Jakiro's early pushing ability from Liquid Fire makes Jakiro very strong against heroes, that take a long time to get online: Morphling, Naga Siren, Spectre.

* Jakiro's abilities deal damage over time, which can disrupt Magnus's attempts to initiate with Blink Dagger and Reverse Polarity.
* Macropyre not only disables Blink Dagger for a considerable duration, but can also destroy Trees, revealing Magnus's cover and position.

* Axe is a hero that is very vulnerable against magical nuke damage and disables, Jakiro is perfect against him with all of his spells.
Additional:
* Ice Path neutralizes initiation attempts with Berserker's Call, and its long area of effect discourages follow-up from Axe's teammates.
* Ice Path serves as a large obstacle to stop Axe from chasing down fleeing stragglers to kill with Culling Blade.
* Jakiro's many damage-per-second skills prevent Axe from initiating with his Blink Dagger.

* Both Ice Path and Macropyre are the good setup while Earthshaker after blinking in and stay out of Echo Slam initiation radius.
* Liquid Fire damage over time potentially disable Earthshaker's Blink Dagger.

* 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 with illusion and clone abilities may confuse Bloodseeker, causing him to waste time in fights: Phantom Lancer, Chaos Knight, Arc Warden

* Single-target disablers will have difficulty locking down a Chaos Knight with Phantasm active: Bane, Beastmaster, Bloodseeker, Clockwerk, Doom, Shadow Shaman.