* 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.

* Both Hoof Stomp and Double Edge can hit Slark during Shadow Dance, the latter requiring a unit nearby for the ability to be cast on.
* Slark has very low health in the early game, making him susceptible to the burst from Double Edge.

* 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.

* He can't take you very easily, and his nukes are not strong enough to deal with Centaur Warrunner.
* Centaur Warrunner deals huge AoE damage and applies an AoE disable through Hoof Stomp, affecting the double as well the main Arc Warden.
* Magnetic Field is not very effective against melee heroes.
* This ability also increases his allies' attack speed, meaning Retaliate will deal more damage.
* Stampede catches him easily due to the lack of escape mechanisms.

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

* Centaur can use Stampede to break Static Link. It also prevents Razor from chasing Centaur Warruner or his teammates with Eye of the Storm, and Plasma Field's slow will do nothing to slow them down.

* Whenever Doom casts his ultimate, Centaur Warrunner can cast Stampede and allow the Doomed hero to run away, wasting Doom's ultimate.
Additional:
* Stampede can be used to free an ally from the grasp of Doom. Without any means of effective lockdown, kills can be difficult to secure when against an enemy Centaur Warrunner.

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

* Retaliate deals damage to Phantom Assassin for every attack and Stifling Dagger thrown at Centaur.
* Blur cannot evade Double Edge.
Additional:
* Retaliate turns Phantom Assassin's attacks against herself, as he deals damage with every hit taken, and his big health pool makes sure that a lot of hits will be needed.
* If Centaur Warrunner gets the jump on Phantom Assassin first, she will be unable to activate Black King Bar and might be burst down with the help of his Double Edge.
* Stampede can save an ally under attack by Phantom Assassin, offsetting the slow from Stifling Dagger. If he owns an Aghanim's Scepter, he can prevent a low-health ally from being killed in one crit.

* Troll Warlord's high speed attack makes Retaliate deal a lot of damage to him.

* 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.

* Night Stalker is all about right-clicks. His nuke, Void is also not that threatning once you have Hood of Defiance, your core item.

* 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.

* 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.

* 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.

* 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.

* A good Centaur can catch Queen of Pain with a Blink Dagger and Hoof Stomp.
* Retaliate with Blade Mail reflects all of Queen of Pain's damage, especially Sonic Wave.
* Stampede grants a movement speed bonus, which can prevent Queen of Pain from initiating.
* Double Edge can shred her low health pool if she's not careful.

* 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 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.

* 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!.

* A Blink Dagger combined with Hoof Stomp can be used to catch Sniper.
* Centaur can also utilize Stampede to cover the distance.
* Double Edge can easily finish off Sniper after Centaur initiates on him.
* Retaliate punishes Sniper for focusing Centaur in teamfights.
Additional:
* Headshot and Shrapnel slow is ineffective against a team with haste (which Stampede gives).
* Commonly picked up mobility items and hasted movement during his Stampede (as well as his high health pool) make him extremely hard to kill from a distance, damaging Sniper with Retaliate and Blade Mail if he has one.
* A low health pool and no escape mechanism makes him an easy target for Centaur Warrunner's burst damage and initiation (even making his team possible initiators with Stampede).

* 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.

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

* 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.

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

* Heroes with haste can negate Enchant's slow: Weaver, Dark Seer, Lycan, Centaur Warrunner.

* 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.

* Heroes who can match Void Spirit's mobility (like the aforementioned Ember Spirit or Queen of Pain) or tank his spells (Dragon Knight or Centaur Warrunner) are very problematic for him.

* Durable heroes can stand against Tusk during 1v1: Axe, Dragon Knight, Night Stalker, Centaur Warrunner, Wraith King and more.

* 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.

* 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 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.

* 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 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.

* When Swashbuckle hits Centaur Warrunner, Return will deal significant damage, as it procs off every strike made.
* Stampede helps allies avoid or disengage from Pangolier during Rolling Thunder, as well as neutralizing the slow debuff from Lucky Shot.

* Stampede can help his teammates escape from Windrun and Focus Fire.
* Return will shred through Windranger's health if she chooses to attack him during Focus Fire.
Additional:
* Focus Fire grants Windranger a massive attack speed bonus, while her attack damage is generally quite low. This, combined with Windranger's low health pool and armor, makes Retaliate do absolutely massive damage over a short time, making Centaur a hero she can never expect to kill or harass.
* Windrun grants evasion, but Centaur Warrunner does not rely on successful attacks in order to do damage. Hoof Stomp, Double Edge, and Stampede all do large amounts of magical damage and can completely demolish Windranger in a moment.

* 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.

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

* Hoof Stomp and Double Edge makes short work of Phantom Lancer's illusions.
* Retaliate together with Blade Mail reflects Phanton Lancer's damage.
Additional:
* His illusions will kill themselves in a few hits because of Retaliate. The nukes from Hoof Stomp and Double-Edge should be enough to clear them for a large portion of the game
* Centaur Warrunner's small mana pool makes Diffusal Blade's damage much lower once Centaur doesn't have any more mana left to burn. Keep in mind that Double Edge does not cost mana.
* Be wary when chasing down Phantom Lancer. Hoof Stomp's terrible cast time makes it quite easy to dodge with Doppelganger.

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

* Heroes who are reliant on illusions: Chaos Knight, Phantom Lancer, Naga Siren.

* They are both nukers, but Centaur Warrunner has superior health and strength gain.
* Centaur's low Intelligence makes Mana Burn do low damage.
* Bar some creative skill builds, Centaur's Hoof Stomp stun duration should always last longer than Spiked Carapace stun, so escaping unscathed is hard for Nyx.
* With Blink Dagger and detection, Centaur can devastate Nyx in the open.