From Dota 2 Wiki
- Dispel Magic from Storm can instantly kill the Phantasm army early game and can still deal a lot of damage to them late game, revealing the real Chaos Knight.
- Dragon Blood's armor bonus greatly reduces the damage dealt by Phantasm and negates Reality Rift's debuff.
- Breathe Fire and Elder Dragon Form's splash damage quickly destroy illusions.
- Echo Slam will deal colossal amount of damage to your army, as will Fissure at lower levels.
- The area stuns from Aftershock will always slow down your illusions, since they can't have Spell Immunity.
- Black Hole usually catches Chaos Knight with all his illusions.
- Midnight Pulse deals damage based on max health, quickly killing Phantasm illusions.
- Using Reality Rift sets up a Reverse Polarity on Chaos Knight and his illusions.
- Shockwave and Skewer kill Phantasm illusions quickly, as can Empower cast on a melee carry.
- Purification heals a teammate targeted by Reality Rift and heavily damages Chaos Knight and his illusions.
- Repel prevents pick-offs via Reality Rift (barring level 25 ) and Chaos Bolt.
- Guardian Angel blocks Chaos Knight's damage output.
- Sand King's massive area damage output, particularly Epicenter, allows him to quickly take down Chaos Knight and his illusions.
- He can apply Caustic Finale to illusions with attacks for extra damage.
- Decrepify turns the target ethereal, protecting them from Reality Rift.
- Life Drain instantly destroys illusions. It can effectively negate Phantasm when upgraded with Aghanim's Scepter.
- Nether Blast quickly clears out illusions and can harass Chaos Knight in lane.
- Sven's shorter cast time allows him to Storm Hammer Chaos Knight and his illusions before he can cast Chaos Bolt.
- Warcry's armor bonus counteracts Reality Rift and reduces Chaos Knight's damage output.
- Great Cleave and God's Strength devastate Phantasm illusions.
- Ravage damages and disables Chaos Knight's army.
- Anchor Smash deals respectable area damage at early levels and debuffs Chaos Knight's damage.
- Kraken Shell removes Chaos Bolt and Reality Rift while providing protection from damage.
- Strong area damage, particularly from Chakram, lets Timbersaw clear out illusions quickly.
- Reactive Armor quickly builds stacks against Phantasm illusions, making Timbersaw hard to kill.
- Timber Chain allows Timbersaw to escape while surrounded.
- Cold Embrace protects targets of Reality Rift.
- Winter's Curse turns Phantasm illusions against Chaos Knight or a teammate.
- Splinter Blast deals decent area damage to Phantasm illusions.
- Arctic Burn's percentage-based damage quickly wears down Chaos Knight's health.
- Heroes with strong area damage to destroy Phantasm illusions: Axe, Ember Spirit, Phoenix.
- Heroes that can instantly destroy illusions greatly reduce Phantasm's effectiveness: Lion ( Mana Drain, Hex), Outworld Devourer ( Arcane Orb), Disruptor ( Glimpse), Shadow Shaman ( Hex), Medusa ( Stone Gaze).
- Illusion-based and multi-unit heroes can take advantage of Chaos Knight's lack of area damage: Naga Siren, Phantom Lancer, Meepo, Broodmother.
- Shiva's Guard provides armor and a negative attack speed aura, reducing the damage output of Chaos Knight and his illusions, and can slow and damage them with Arctic Blast.
- Blade Mail is a great item when timed right to destroy all the illusions instantly and it does a great job in countering Chaos Knight's high damage output in general.
- Butterfly and Solar Crest allow heroes to evade Chaos Knight's attacks, reducing his damage output.
- Ghost Scepter and Ethereal Blade prevent Chaos Knight from focusing down a target by turning it ethereal.
- Manta Style creates illusions that can make it difficult for Chaos Knight to initiate on the real hero.
Good against...Bounty Hunter
- 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 Reality Rift.
- Berserker's Blood and Inner Vitality are of little use against Chaos Knight's physical burst damage.
- Phantasm and Reality Rift can be used to counter-initiate against Life Break.
- Chaos Bolt locks down Huskar for an easy kill.
- Reality Rift lets Chaos Knight bypass the Spirit Bear and jump on Lone Druid.
- The Spirit Bear's lack of scaling means it dies quickly to Chaos Knight during the late-game.
- Phantasm illusions make it difficult to land Meat Hook and Dismember.
- Chaos Strike's lifesteal offsets Rot's damage.
- Chaos Bolt and Reality Rift both interrupt Dismember with a comparatively low cooldown.
- Casting Phantasm before a fight minimizes the disruption from Global Silence.
- Dark Pact is minimally effective against Phantasms, 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.
- Phantasm illusions can be used to push towers and force Techies to detonate Remote Mines.
- Phantasm illusions can be used to sweep Proximity Mines and Stasis Traps.
- Chaos Knight can easily kill a lone Techies before they Blast Off!.
- Ursa cannot effectively fight against Phantasm illusions with his single-target damage.
- Chaos Bolt's long stun gives Ursa little opportunity to Enrage.
- As Viper focuses on single-target damage, he has trouble fighting off Phantasm illusions.
- Reality Rift counteracts Viper's slows and reduces his durability.
- Phantasm gives Chaos Knight a significant advantage against single-target damage dealers: Lifestealer, Wraith King, Night Stalker.
- Single-target disablers will have difficulty locking down a Chaos Knight with Phantasm active: Bane, Beastmaster, Bloodseeker, Clockwerk, Doom, Shadow Shaman.
- Innately fragile heroes will die almost instantly to Reality Rift while Chaos Knight has illusions active: Drow Ranger, Bane, Necrophos, Crystal Maiden.
Works well with...Crystal Maiden
- Arcane Aura helps sustain Chaos Knight's limited mana pool.
- Frostbite and Crystal Nova provide decent set-up for Chaos Knight's spells.
- A 4 second Chaos Bolt stun can render an enemy helpless against Freezing Field.
- Berserker's Blood gives Huskar high magic resistance, countering Chaos Knight's weakness to area-of-effect spell damage.
- Chaos Knight can deal with single-target physical damage, which would otherwise shut down Huskar.
- In lane, Mana Leak can set up Chaos Knight's spells or remove the enemy's mana and prevent them from threatening Chaos Knight.
- Chakra Magic solves Chaos Knight's mana issues.
- Chaos Bolt provides setup for Illuminate.
- The heal from Illuminate during daytime helps keep Phantasm illusions alive.
- Recall helps Chaos Knight get around the map and siege different lanes.
- Disruption can create two Chaos Knight illusions to inflict more damage on the enemy.
- Disruption and Demonic Purge allow Chaos Knight to more easily approach slippery enemies.
- Reality Rift can set up Soul Catcher, which in turn amplifies Chaos Knight's single-target damage.
- Armor reduction considerably boosts Chaos Knight's damage output, especially area debuffs which allow Chaos Knight to pick off more enemies: Vengeful Spirit, Alchemist, Dazzle, Slardar.
- Any hero that can make good use of Chaos Bolt's stun to land delayed or damage over time abilities: Skywrath Mage, Invoker, Jakiro.