* 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 and mutes 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.

Additional:
* Phantom Lancer's strength is the sheer amount of illusions he can conjure, Dissimulate can be cast on an ally that he is focusing to quickly thin out his ranks
* Landing a upgraded Demonic Purge on the real Phantom Lancer prevents him from making very many illusions (His only source being Doppelganger), You can reapply as needed if you have the Shard
* Disrupting Phantom Lancer allows you to create multiple extra illusions with Juxtapose, As he is a common carrier of Diffusal Blade, you can also drain the mana of any nearby heros

* 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 Scepter it will also take away glaive bounces and extra damage from Luna's passive. And Luna's commonly items Manta Style and Black King Bar does not work dispell to Demonic Purge
* Luna's illusions created by Disruption are 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.
* For the same reasons, Shadow Demon makes a very powerful ally for Luna when they are in the same team.
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 are 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.
* For the same reasons, Shadow Demon is a very good ally for Luna when they are in the same team.

* Melee carries such as Sven, Ursa or Lifestealer can be slowed and easily kited with Demonic Purge.

* Generally, any fragile heroes will have a hard time dealing with Undying's tankiness, and even more so if Decay is used on them. Some examples are Crystal Maiden and Witch Doctor.

* 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.

* Her illusions with Desolate are 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 and allow your allies to finish her off.
* If she tries to kill you or any key ally with Haunt at any point of the game, remember to not panic and always use Disruption 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.

* Spectre must chase for kills and relies on movement speed for mobility in fights, and has no way to counter the Tombstone zombies.
* The potency of Soul Rip can be increased from nearby illusions from Haunt.
* Decay will shut down Spectre during the laning phase by effectively cutting down her initial health pool.
Additional:
* Spectre must chase for kills and relies on movement speed for mobility in fights, and has no way to counter the Tombstone zombies.
* The potency of Soul Rip can be increased from nearby illusions, so Undying can use Haunt against Spectre.
* Early game Decay will make Spectre easy to shut down in lane.

* 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 reaches a new power spike and becomes 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.

* Undying can use Decay not only to reduce Sven's maximum health, but also to reduce the damage he can deal with his ultimate.
* Zombies spawned by Tombstone together with Flesh Golem slow Sven down significantly. Landing Sven's powerful but somewhat slow right-click on Tombstone would be a waste.

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

* Decay, Soul Rip and Flesh Golem all deal magical damage which ignores Bulwark.
* Decay reduces Mars' natural strength and therefore his health pool, which is what he relies on to trade effectively in lane.

* Shadow Demon's Demonic Purge with Aghanim's Scepter disables Bristleback's passives.

* Undying's Decay is a dangerous ability against Bristleback, as it makes him more vulnerable and reduces his tankiness.
* Undying's Tombstone together with Flesh Golem can slow Bristleback down significantly.

* Heroes with ways to protect themselves or allies from Spirit Breaker's initiation: Shadow Demon, Outworld Destroyer, Omniknight, Dawnbreaker.

* Due to Spirit Breaker's low attack speed, Tombstone is problematic for Spirit Breaker as the zombies summoned from Tombstone apply a stacking movement speed slow, which can significantly reduce Greater Bash's damage.
* Soul Rip and Decay allows Undying and his allies to survive and recover from any incoming ganks by Spirit Breaker.

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

* Shadow Demon's spammable illusions can be used to scout Techies' Proximity Mines.

* Disruption can banish Faceless Void or an ally in Chronosphere, making it a less effective 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.

* Undying's Tombstone will cheerfully chew through treants, incidentally netting you some extra income during fights.
* The above interaction tends to ensure that skirmishes are heavily populated with units, thereby buffing Soul Rip

* 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.

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

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

* Decay can be good against Centaur Warrunner, as reducing the health of Centaur can make Double Edge risky.
* His zombies do not proc Retaliate, as it only procs for regular attacks.

* Disruption will save Shadow Demon's teammates from being killed by Counter Helix or Culling Blade.
* 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.
* Demonic Cleanse clears Battle Hunger and Aghanim's Shard Counter Helix Damage Reduction, both allowing targets to escape and reducing your own survivability.
Additional:
* While it is unwise to encounter Axe alone, Disruption can be used to save your allies from Axe's initiate Berserker's Call, or, if timed correctly, from his Culling Blade.
* Illusions spawned from Axe has the Counter Helix passive, which with deal some nasty damage if an enemy focuses them
* Your upgraded Demonic Purge breaks Axe's primary damage output: Counter Helix, This can be used on him during Berserker's Call to seriously hinder him.
* Demonic Cleanse will clear Battle Hunger, which is Axe's method of catching heroes, and Shard upgraded Counter Helix's Damage Reduction, which is one of Axe's primary survivability abilities.

* Undying saps strength from heroes with Decay, and Ogre Magi's high strength gain will allow Undying to steal more and more strength, becoming stronger with each use.
* Due to the Strength steal from Decay, Undying is normally very tanky, and has high health, making it harder for Ogre Magi to kill him.

* Shadow Demon's Disruption will allow his allies to maneuver around you. It can also be used to protect an ally from your abilities, or Astral Imprisonment - Meteor Hammer combo.
* Disseminate turns your high damage Arcane Orb and Sanitiy's Eclipse against you and your teammates.
* Scepter upgraded Demonic Purge will break your Essence Flux passive for 7 seconds, preventing you from regaining mana, and severely hindering your damage output.

* Winter Wyvern cannot handle the Zombies created by Undying's Tombstone very well. In most situations, Zombies will have more movement speed than her.
* Undying can gain one or two easy Decay stacks on an ally in Cold Embrace. The ally will still take the damage as well.
Additional:
* Winter Wyvern cannot handle the Zombies created by Tombstone very well. In most situations, Zombies will have more movement speed than her.
* Undying can gain one or two easy Decay stacks on an ally in Cold Embrace. The ally will still take the damage as well, since it is magical.

* 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 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 with break can disable Untouchable for a while: Doom and Shadow Demon (via Aghanim's Scepter), Viper, Shadow Shaman with Hex Breaks talent.

* 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.

* Primal Beast really suffers against supports he cannot bully in the lane: this includes Dazzle, Shadow Demon and Dark Willow since they can use their respective abilities to stop Primal Beast from dealing burst damage, or make it hard for him to stay in range.

* 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 reaches a new power spike and becomes 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 a slow attack rate will find themselves struggling to take out Tombstone, like Doom.

* Anti-Tank heroes like: Razor, Necrophos, Undying.

* Generally, any fragile heroes will have a hard time dealing with Undying's tankiness, and even more so if Decay is used on them. Some examples are Crystal Maiden and Witch Doctor.

* 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 reaches a new power spike and becomes 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.

* Similarly, they can negate your X Marks The Spot & Torrent combo by protecting your target when you use Return. Good candidates to negate your combo include Outworld Destroyer and his Astral Imprisonment, and Shadow Demon and his Disruption.
* Heroes with hide abilities can often dodge a Ghostship just before it hits.
* Similarly, they can negate your X Marks The Spot & Torrent combo by protecting your target when you use Return. Good candidates to negate your combo include Outworld Destroyer and his Astral Imprisonment, and Shadow Demon and his Disruption.
* A Eul's Scepter of Divinity can also do the trick, but, unlike the previously mentioned abilities, you can only use it on yourself and not your allies.

* Hex abilities prevent attacking, ability and 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: Doom, Disruptor with Aghanim's Scepter, Dazzle with Aghanim's Shard

* Melee carries such as Sven, Ursa or Lifestealer can be slowed and easily kited with Demonic Purge.

Additional:
* Shadow Demon's Demonic Purge renders Ursa useless even through Black King Bar as it slows him, continually purges his Overpower charges and can not be dispelled by Ursa's Enrage.
* Disruption is a good way to save teammates against Ursa. Disrupting Ursa is also a good way to kite him, as it can not be dispelled by Enrage.

* 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.

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

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

* Heroes with abilities that can save teammates 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 who can hide the Dueled target (Outworld Destroyer, 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.

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

* Shadow Demon's Shadow Poison can quickly stack to the point where Huskars generally low health is easily finished off.
* Shadow Demon's Disruption can turn Huskar's high attack speed and regeneration against him, It also makes him an easy target for Shadow Poison,
* Shadow Demon commonly builds a Meteor Hammer, allowing him to land a heavy stun on Huskar
* Shadow Demon's upgraded Demonic Purge breaks Huskar, It also pierces Spell Immunity, Without his passive for 7 seconds Huskar quickly falls in battle
* However note that Shadow Demon is a squishy target and you can often overwhelm him if he is alone, But he can still Disrupt you to escape
Additional:
* Shadow Poison can quickly stack up on Huskar, And with his naturally low health you don't need as many stacks to be effective.
* Disruption turns Huskars high attack speed against him, They also have the highest survivability as illusions due to his passive Berserker's Blood, It also allows you to put Shadow Poison stacks on him,
* Dissimulate turns Huskar's burning damage against his team, You can cast it on an ally who is taking a bunch of Burning Spear stacks and cause Huskar to take high amounts of damage as well
* Scepter upgraded Demonic Purge is your most effective weapon against him, It's 7 second Break causes him to quickly die in battle

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

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

* Heroes who can summon illusions and summons because Terrorblade has no abilities to deal with multiple enemies at once outside Reflection: Shadow Shaman, Naga Siren, Broodmother, Lycan, Enigma, Chaos Knight, Phantom Lancer, Shadow Demon, Dark Seer, Nature's Prophet, Invoker, Morphling, Visage, Grimstroke with Aghanim's Scepter.

* Disruption sets up Anti-Mage for a chain disable. The illusions will deal extra damage due to Mana Break.
* Shadow Poison hits Anti-Mage even after he's Blinked away.
* If Shadow Demon has Aghanim's Scepter, Demonic Purge can break Mana Break and Counterspell, weakening both his offense and defense.
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 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.

* Alchemist is a well-known Radiance carrier among other auras your illusions will benefit from. They also get the extra move speed and reduced base attack time from his Chemical Rage, and it's even better if you can catch him as his own rage is about to expire.
* Disruption will buy enough time for all allies to retreat when Alchemist starts to activate Unstable Concoction.

* Heroes with summons or illusions can counter Flux, such as Beastmaster , Chen, or Shadow Demon.