* 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.

* Viper is an agility hero, and his item build mostly includes agility items, so Natural Order can be devastating, removing all armor and greatly decreasing the effectiveness of Corrosive Skin, weakening Viper's magic resistance. Additionally, Echo Stomp and Earth Splitter deal both magical and physical damage, and can help bringing Viper down fast.
* Aghanim's Scepter may be necessary to take Viper down due to Nethertoxin's break.

* Natural Order aura prevents Slark from gaining armor from the agility stolen with Essence Shift.
* Echo Stomp and Earth Splitter can hit Slark through his Shadow Dance ultimate.
* Slark's stats gain is relatively low compared to most agility carries making him quite squishy without his agility-based armor.

* 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.

* Slow heroes that have a hard time escaping the Echo Stomp radius: Crystal Maiden, Pudge, Techies.

* 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!.

* 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.

* Elder Titan's Astral Spirit ability gives him bonus damage for each converted creep it passes through.
* Echo Stomp and Earth Splitter will often kill him or any of his allies quickly before he has time to use Hand of God.

* Astral Spirit can give Elder Titan a lot of damage and movement speed if Nature's Prophet stands close to his treants.
* Not only Echo Stomp can also prevent Nature's Prophet to escape Teleportation, but also, Elder Titan can also use Astral Spirit to bypass Sprout and use its own Echo Stomp.
* Aghanim's Scepter upgraded Earth Splitter can clear Nature's Prophet's treants and disarm him simultaneously, which can shutdown his pushing.

* 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.

* 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.

* 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.

* Most of Morphling's armor comes from his high agility and it is reduced by Natural Order.
* However, the aura has only 350 range and Elder Titan can be bursted down by Morphling's nuke combo if he isn't careful.
Additional:
* Morphling's high armor is primarily from Morphing agility, which is reduced by Natural Order therefore making the hero very vulnerable when it has morphed a lot into agility.
* Morphling usually will Morph into high agility and low strength. This can be taken advantage of with a good stun or silence or by bursting him down before he has the time to Morph back to strength.
* Morphling is very vulnerable to Blade Mail under Natural Order and can easily burst himself down with his own auto-attacks or his magical damage combo.

* Terrorblade has a high base armor, and relies on many ultimate orb-based items (Manta Style and Eye of Skadi). Natural Order affects armor gained from agility, essentially reducing armor to zero if all armor is gained from agility. That effect combined with Terrorblade's low health can make a Elder Titan with an early value point in Natural Order a dangerous foe.
* Terrorblade's illusions are often grouped up in teamfight, making them more vulnerable to Echo Stomp.
Additional:
* Echo Stomp and Astral Spirit allow the enemy team to coordinate a kill on Terrorblade before he can Sunder.
* Natural Order cripples Terrorblade's armor that he crucially needs to survive due to his low strength gain.

* 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.

* Slow heroes that have a hard time escaping the Echo Stomp radius: Crystal Maiden, Pudge, Techies.

* 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.

* 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'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.

* 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.

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

* 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.

* 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.

* 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.

* 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.

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

* 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.

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

* 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.

* 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.

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

* In general, heroes with AoE or long range disables (such as Faceless Void with Chronosphere, Pudge with Meat Hook and Elder Titan with Echo Stomp) hinder Crystal Maiden, preventing her from using Freezing Field to help her team in a fight.

* Skywrath mage also has a terrible time fighting against anything that isn't a hero. As Mystic Flare only affects heroes, his skills are mostly target-based and he has terrible strength and agility, he can easily be kited or harassed by illusion-based heroes like Chaos Knight and Phantom Lancer, or by Heroes that summon other units like Lone Druid, Lycan and Beastmaster.

* 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.

* 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

* Elder Titan's Echo Stomp can turn into a 5 second stun on an ally under the effect of False Promise, as it delays all damage and makes it impossible to break the damage threshold of Echo Stomp.

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

* 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).

* 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.

* 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.

* 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.

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

* Echo Stomp can impede Broodmother's ability to push towers due to its low cooldown and long sleep duration.
* Astral Spirit can provide Elder Titan large amounts of damage, armor, and movement speed from her spiderlings.
* Natural Order negates Broodmother and her spiderling's base armor and magic resistance, increasing most damage dealt to them.

* 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.

* 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.

* Phantom Lancer's lack of disables makes it hard for him to stop Echo Stomp's channelling.
* However, due to the long cast time of his abilities, a good Phantom Lancer can use Manta Style and/or Doppelganger to dodge the abilities.
* Phantom Lancer's high agility and relatively low strength make him very vulnerable to Natural Order.
* Additionally, Echo Stomp and Earth Splitter can clear his wave of illusions.
* Should Phantom Lancer tries to increase his health by investing for Heart of Tarrasque, Earth Splitter does more damage to him and his illusions.

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