* Heroes with abilities that break Berserker's Blood, lowering Huskar's attack speed and health regeneration: Doom, Shadow Demon, Viper.

* Chemical Rage negates almost all damage from Burning Spears.
Additional:
* Chemical Rage mitigates damage from Burning Spear.

* Disruption instantly removes Phantom Embrace, and can potentially save allies affected by Soulbind.
* Demonic Purge dispels Ink Swell.

* Chemical Rage out-heals Doom to a large degree throughout all stages of the game. Should Alchemist be chemically enraged before being Doomed, Alchemist can become a difficult target to effectively lockdown and kill, thanks to the health regeneration and movement speed bonuses granted by his ultimate.
* Alchemist is an ineffective target for Doom. Alchemist isn't totally reliant on his skills to be effective during a teamfight, due to the right-click nature of the hero.

* Shadow Demon's spammable illusions can be used to scout Techies' Proximity Mines. The illusion of your carries can be even used to trick Techies into detonating his precious Remote Mines.

* Shadow Demon can waste precious seconds of Windrun with Disruption.
* Alternatively, Demonic Purge can be used to dispel it altogether, leaving her completely defenseless for 7 seconds.
* Disruption can be used to save an ally if they get stunned by Shackleshot.

* Disruption sets up Anti-Mage for a chain disable. The illusions will deal extra damage due to Mana Break.
* Soul Catcher causes Anti-Mage to take a large chunk of damage, and can hit him when he is inside from Disruption.
* Shadow Poison hits Anti-Mage even after he's Blinked away.
Additional:
* While it is unwise to encounter Anti-Mage alone, Disruption's considerable cast range can become a perfect setup for any hard-disable to follow up. If he is pinned down, Anti-Mage will quickly face his demise when the illusions deplete his already low mana pool. Manta Style will easily allow him to escape, however.
* The illusions can be controlled to quickly sap mana from any other target, making Anti-Mage one of the most valuable targets to disrupt.

* Disruption will save Shadow Demon's teammates from being killed by Counter Helix or Culling Blade.
* Soul Catcher and Shadow Poison can put Axe's Blink Dagger on cooldown.
* Demonic Purge slows Axe to a crawl, making him nearly useless after initiating. If Shadow Demon has Aghanim's Scepter, it will also break Counter Helix.

* The constant dispel from Demonic Purge will make any attempt to save the victim or himself by Surge become futile. For what it's worth, Demonic Purge will also dispel Ion Shell.

* Magnus has very mediocre damage against Alchemist, because he can survive the stun duration of Reverse Polarity with Chemical Rage.

* In the laning stage, making illusions of Venomancer will turn his Poison Sting back at him, making for an easy gank level one, and for later when your mid comes for ganks.

* Alchemist's Acid Spray can heavily damage Chen's creeps and disrupt his jungling.
* Alchemist builds items like Radiance and Battle Fury, allowing him to quickly clear Chen's creeps.
* Alchemist's Greevil's Greed will grant him more bonus gold as he kills Chen's creeps.

* Disruption can banish Faceless Void or an ally in Chronosphere, making it less effective of an ability.
* Faceless Void's illusions created by Disruption will not get stunned by Chronosphere, allowing Shadow Demon to attack Faceless Void in his Chronosphere.
* Casting Disruption after releasing Shadow Poison charges will make Time Walk unable to backtrack the damage.
* Shadow Poison is a good way to deal damage as the initial damage and the release damage can't both be Time Walked at the same time.
* Demonic Purge is a great slow, useful to force out a Time Walk early and can break Time Lock with Aghanim's Scepter.

* Chemical Rage will take down Tombstone in no time.
Additional:
* With Greevil's Greed, Alchemist can farm Tombstone zombies and gain a significant gold advantage.

* Her illusions with Desolate is very valuable, especially when they are usually paired with Radiance. Unlike blink or force movement, Spectral Dagger's escaping mechanic requires manual movement, and therefore Demonic Purge can hold her back really hard allow your allies to finish her off.
* If she would try to kill you or any key ally with Haunt at any point of the game, remember to not panic and always use Disrupt on the illusion, whether it is fake or the real Spectre herself. When the situation calls, Demonic Purge can save a second victim from a haunting Spectre.
* When upgraded by Aghanim's Scepter, Demonic Purge can remove Spectre from a fight by disabling Desolate and Dispersion, negating her damage and tankiness respectively.

* Alchemist can easily farm Spiderlings with Acid Spray and Greevil's Greed.
* Alchemist's Chemical Rage nullifies Broodmother's Insatiable Hunger
Additional:
* Greevil's Greed makes Broodmother’s spiderlings far more valuable to Alchemist making it important that he does farm them as opposed to other heroes where the spider's bounties are negligible.
* Acid Spray makes it difficult to attack Alchemist in lane without losing some spiderlings to the damage over time, potentially giving him farm he wouldn't have otherwise.

* Heroes with high physical damage output but lack of reliable escape mechanisms are always a good target for a solo gank: Sniper, Shadow Fiend, Troll Warlord, Drow Ranger. Those heroes, however, are dangerous if they manage to close the gap, so take caution.

* Shadow Demon's Soul Catcher hinders Bristleback's tanking capabilities. Demonic Purge with Aghanim's Scepter disables Bristleback's passive.

* Heroes with high physical damage output but lack of reliable escape mechanisms are always a good target for a solo gank: Sniper, Shadow Fiend, Troll Warlord, Drow Ranger. Those heroes, however, are dangerous if they manage to close the gap, so take caution.

* Heroes with high physical damage output but lack of reliable escape mechanisms are always a good target for a solo gank: Sniper, Shadow Fiend, Troll Warlord, Drow Ranger. Those heroes, however, are dangerous if they manage to close the gap, so take caution.

* Heroes with break abilities: Nyx Assassin, Shadow Demon (with Aghanim's Scepter), Viper.

* Doom, Disruptor with Aghanim's Scepter, and hex abilities all prevent item usage, which is a severe problem for Phantom Assassin as it prevents her from using Black King Bar, the one item that helps protect her against the aforementioned dangers. Doom and Shadow Demon with Aghanim's Scepter also disables Phantom Assassin's Evasion and Critical Strike, removing much of her damage and survivabaility.

* Heroes that lose a great amount of their tankiness and become easier to finish off: Bristleback, Spectre, Phantom Assassin, Enchantress, Dragon Knight.
* Once you have an Aghanim's Scepter, Shadow Demon instantly reach a new power spike and become a counter for a variety of heroes that have strong passives.
* Heroes that lose a great amount of their tankiness and become easier to finish off: Bristleback, Spectre, Phantom Assassin, Enchantress, Dragon Knight.
* Heroes that lose a great amount of damage output and become less threatening: Phantom Assassin, Sven, Slark, Phantom Lancer.
* You can always stack camps and farm the scepter with Shadow Poison.

* Heroes that can dominate his illusions or create their own illusions of him: Dark Seer, Morphling, Enchantress, Shadow Demon.

* Heroes that can gain vision over trees to catch Tinker: Invoker, Shadow Demon, Batrider

* Heroes with abilities that can save are also effective such as Shadow Demon, Dazzle, Oracle, Bane, Pugna, Tusk, Winter Wyvern, Io, Underlord, Treant Protector and Keeper of the Light.

Additional:
* Be ready to save an ally from Omnislash with your Disruption.
* Spawning Juggernaut's illusions is a great deal, as his base attack time is low and he has a critical strike. Illusions will benefit from both.
* Demonic Purge will prevent Juggernaut's desperate attempt to flee using Blade Fury. However, it cannot stop him if he is using Town Portal Scroll.

* 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).

Additional:
* Demonic Purge takes off Luna's superior mobility, removing the need for chasing her and allowing your team to reposition in team fights or escape when at low HP. If Shadow Demon has Aghanim's Sceptre it will also take away glaive bounces and extra damage from Luna's passive.
* Luna's illusions created by Disruption is very valuable with their Moon Glaives. These will effectively counter her pushing attempts and are painfully effective in team fights.
* Disruption can be used to save an ally from Eclipse.

* Heroes with ways to protect themselves or allies from Spirit Breaker's initiation: Shadow Demon

* Heroes with hiding abilities can protect disabled allies: Outworld Devourer, Shadow Demon, Tusk, Phoenix with Aghanim's Scepter

* Heroes that lose a great amount of damage output and become less threatening: Phantom Assassin, Sven, Slark, Phantom Lancer.
* Once you have an Aghanim's Scepter, Shadow Demon instantly reach a new power spike and become a counter for a variety of heroes that have strong passives.
* Heroes that lose a great amount of their tankiness and become easier to finish off: Bristleback, Spectre, Phantom Assassin, Enchantress, Dragon Knight.
* Heroes that lose a great amount of damage output and become less threatening: Phantom Assassin, Sven, Slark, Phantom Lancer.
* You can always stack camps and farm the scepter with Shadow Poison.

* Heroes with summons or illusions makes Sacred Arrow harder to land: Shadow Demon, Phantom Lancer, Nature's Prophet.

* Heroes that can punish aggressive heroes, such as: Leshrac, Shadow Demon, Pugna, Death Prophet.

* Heroes with high physical damage output but lack of reliable escape mechanisms are always a good target for a solo gank: Sniper, Shadow Fiend, Troll Warlord, Drow Ranger. Those heroes, however, are dangerous if they manage to close the gap, so take caution.

* Acid Spray and Greevil's Greed will quickly destroy pushes with treants.

* Disruption can protect Shadow Demon's allies from Fortune's End, preserving healing or buffs. It can also catch Oracle's allies, allowing Shadow Poison and Soul Catcher to be used without being dispelled.
* Demonic Purge prevents over-time healing during False Promise, such as Purifying Flames and Urn of Shadows. If he has Aghanim's Scepter, this issue can persist for longer or on multiple allies.
* It will not, however, prevent healing from instant abilities, items, or auras, making Mekansm a good choice against him.

* Shadow Demon with an Aghanim's Scepter will use Demonic Purge to disable Curse of Avernus and the passive component of Borrowed Time. If this is combined with a silence, Borrowed Time will not trigger at all.
* Even without Aghanim's Scepter, he can still waste Borrowed Time with Disruption. Curse of Avernus fully works on illusions, turning the passive ability against him.

* Heroes that require burst damage to kill will be difficult for Phantom Lancer to take down: Timbersaw, Axe, Bristleback, Alchemist and Underlord

* Shadow Demon's Demonic Purge is undispellable.
* Heroes with undispellable debuffs will help identify the real Phantom Lancer through visual effects or debuff indicators, provided that it was cast on the real Phantom Lancer to begin with:
* Doom's Doom marks Phantom Lancer with a highly visible effect, and also silences him.
* Bloodseeker's Rupture shows a clear red trail effect on the real Phantom Lancer.
* Ancient Apparition's Ice Blast will only debuff Phantom Lancer and not his illusions.
* Grimstroke's Soulbind is undispellable.
* Shadow Demon's Demonic Purge is undispellable.
* Monkey King's Jingu Mastery is undispellable and puts a big yellow Mark over his head.

* Heroes who can hide the Dueled target (Outworld Devourer, Shadow Demon, Tusk, Phoenix with Aghanim's Scepter etc).

Additional:
* Disruption can save allies and mess up an initiation from an enemy Legion Commander. Using Disruption on your ally that is affected by Duel will leave her totally exposed without the benefit of the life steal from Moment of Courage. A precise decision to Disrupt Legion Commander or her victim is crucial to waste Duel's potential.
* Demonic Purge cannot be dispelled by a hard dispel from Press the Attack, which in turn can be dispelled by your ultimate.

* Shadow Demon, Outworld Devourer and Tusk can all save a Lasso'd teammate with their defensive spells.

* Chemical Rage kills Phoenix very quickly in Supernova.

* Disruption can save an ally from a fatal Reaper's Scythe.
* Demonic Purge can remove Ghost Shroud, making Necrophos vulnerable to physical damage and preventing him from regenerating health.

* Heroes with summons or illusions to counter Flux, such as {Hero ID:Beastmaster} , Chen, or Shadow Demon.

* Heroes that can purge buffs can dispel Guardian Angel: Invoker, Shadow Demon, Oracle.

Additional:
* Demonic Purge can dispel Guardian Angel on the key target during combat, allow your allies to finish them.