* Heroes that can slow Charge of Darkness by a huge amount: Venomancer, Viper, Dazzle, Arc Warden

* Pit of Malice can be cast in the path of Spirit Breaker's Charge of Darkness to cancel it.
* Dark Rift provides a way to escape from a gank for Underlord and his teammates.

* Any hero that can outrange Plague Ward can neutralize them without putting themselves at risk of receiving Poison Sting: Arc Warden, Chen, Clinkz, Drow Ranger, Lina, Mirana, Nature's Prophet, Pugna and Sniper.
* Special mention to heroes has attack range talent can also outrange Plague Ward.

* Dark Rift allows Underlord to transport allies from poison damage-over-time to the fountain.
* Underlord usually buys Pipe of Insight that gives a magic resistance to allies, inhibiting the damage from Venomancer abilities.

* Damage reduction from Atrophy Aura prevents Bloodseeker from killing targets and gaining his Thirst bonuses.
* Pit of Malice's area of effect catches Bloodseeker easily, negating his speed bonus during teamfights.
* Dark Rift allows Underlord to transport Ruptured allies to the fountain, rendering it useless.

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

* Underlord can not only cancel Marksmanship's aura, but his Atrophy Aura also decreases Drow Ranger's attack damage.

Additional:
* Atrophy Aura reduces Drow Ranger's damage significantly, as she relies on agility.

* Magnetic Field cause attacks from Drow Ranger outside to miss, forcing Drow Ranger to go inside the field, nullifying marksmanship.
Additional:
* Magnetic Field protects Arc Warden and allies from Drow Ranger's ranged attacks. She most likely will not enter the field since she will lose Marksmanship's bonus agility.

* Arc Warden's Flux tears through Refraction charges almost instantly. Should he have a Tempest Double and no creeps are around, a 75% slow means almost certain death.
* Meld is useless against Spark Wraith.
Additional:
* Flux wastes Templar Assassin's Refraction unless she has a Black King Bar or a Manta Style.
* Spark Wraith can be used to bully a Templar Assassin that used Meld.

* Firestorm will destroy Refraction charges very quickly.
* Firestorm will hit Templar Assassin while Melded.
* Templar Assassin has a hard time maneuvering around Pit of Malice.

* Firestorm quickly kills all the treants and increases the Atrophy Aura passive.
* Pit of Malice can stop Teleportation channeling.
* Atrophy Aura greatly reduces Nature's Prophet's damage and he has no other ways of dealing damage.
* Dark Rift can counter split-pushing, which is something that Nature's Prophet relies a lot, and Nature's Prophet has very little solutions to intercept Dark Rift.

* Magnetic Field makes Impetus miss; if Enchantress decides to enter the field, she is giving up bonus damage since Impetus deals greater damage at higher distance away from targets.

* Magnetic Field evades most of Gyrocopter's attacks.
* Necronomicon can kill Gyrocopter with the summons. In addition, Last Will might activate if the Necronomicon Warrior gets killed through Flak Cannon or Call Down.

* Arc Warden can turn Puck's Phase Shift ability against him by using Spark Wraith, ensuring it to hit. To make this worse, Arc Warden can do it twice with his Tempest Double.
* Flux is also an instant spell (and therefore unavoidable) with a heavy slow and damage over time, which disables Blink Dagger for a certain period of time.

* Arc Warden can counter Morphling's strong pushing capabilities by using Magnetic Field to protect buildings.
* Arc Warden also often builds an Orchid Malevolence or Bloodthorn, which can prove dangerous for Morphling.
* Arc Warden can easily break Linken's Sphere with Flux and then slow him with Spark Wraith, making Arc Warden's Tempest Double a legitimate threat as well.

* Underlord's Atrophy Aura reduces Morphling's high base damage gained through agility shift.

* Arc Warden’s Magnetic Field allows him to defend against Terrorblade if he used Metamorphosis.
* Arc also buys a Bloodthorn or a Scythe of Vyse, which can prevent Terrorblade from using his abilities.

* Unlike other illusion heroes, Tempest Double won't be instantly destroyed by Stone Gaze since it is considered a clone and not an illusion.
* He can use either his own or his double's Flux to bypass the spellblock from Linken's Sphere, using the leftover Flux + Spark Wraith to slow Medusa's move speed to a crawl.
* Arc Warden has a farming advantage with double Hand of Midas, and can generally bully Medusa with other items that benefit from duplication.

* Sonic Wave is a bad choice in abilities if he and the Tempest Double both use Necronomicon and Blade Mail to reflect the damage to Queen of Pain, potentially killing her outright if her health is low enough.
* Magnetic Field protects himself or his ally from Queen of Pain's attacks unless she has Monkey King Bar.
* One more advantage of Tempest Double is that he can deny himself if he is close to death with Shadow Strike's debuff.

* Firestorm and Pit of Malice are very disruptive in team fights, completely matching Mars especially since it can all be cast inside Arena Of Blood and also does percentage-based magical damage, negating Bulwark.
* Dark Rift can save any allies of Underlord trapped in Arena Of Blood.
* Atrophy Aura allows Underlord to lane against Mars quite well since he does not have the best base damage during the early game.
* Underlord is a common carrier of both Pipe of Insight and Mekansm/Guardian Greaves, allowing his team to combat Mars in the mid to late game.

* Atrophy Aura decreases Troll Warlord's damage.
* Pit of Malice helps lock down Troll Warlord.
* Battle Trance disallows Troll from running out of both Firestorm and Pit of Malice.

* His Tempest Double is not an illusion, but rather a full hero unit, which effectively reduces half of the Supernova's health. His Magnetic Field can tremendously boost his attack speed, allowing him to destroy Supernova in no time even when he's affected by Fire Spirits.
Additional:
* Tempest Double, Magnetic Field's attack speed bonus, and Arc Warden's high attack range will easily destroy a Phoenix using Supernova much faster than usual.
* Phoenix is very weak against pushers, especially those like Arc Warden who can kill him easily, as his skillset works best in teamfights.

* Heroes with abilities that blind or cause Legion Commander to miss will prevent her from winning Duels: Arc Warden, Keeper of the Light, Riki

Additional:
* Magnetic Field prevents Legion Commander from getting wins with Duel.

* Atrophy Aura's percentage-based damage reduction greatly diminishes Legion Commander's overall damage output, even if she has won many Duels.
* Dark Rift can be used to save Underlord or his allies from Duels if properly timed.
Additional:
* Atrophy Aura makes it hard for Legion Commander to win Duels.
* Dark Rift can be used to save Underlord and his allies from a Duel.

* Flux will slow and damage Mirana even after she Leaps, since she will likely not be near allies.
* Arc Warden can place Magnetic Field on an ally who has been hit by Sacred Arrow to protect them.
* As Necronomicon is his core item, Arc Warden can reveal Mirana and her allies hiding in Moonlight Shadow and the Necronomicon Warrior can kill Mirana with Last Will if he is unintentionally killed with Starstorm upgraded by Aghanim's Scepter or Sacred Arrow.
Additional:
* If Arc Warden builds Necronomicon 3 he can reveal Mirana's team while Moonlight Shadow is active.
* A Starstorm upgraded by Aghanim's Scepter can accidentally kill a Necronomicon Warrior, which can lead to her death if she hasn't built a Black King Bar.
* Arc Warden can use his summons to prevent Sacred Arrow from hitting himself or his allies.
* Mirana doesn't build items that give armor often, so she usually can't fight against a late game Arc Warden.

* In general, melee heroes without blink mechanisms or spell immunity will have a hard time positioning against Pit of Malice: Sven, Tiny, Wraith King, Dragon Knight, Meepo, Doom, Bounty Hunter, Dark Seer, Undying, Alchemist, Legion Commander.

* In general, melee heroes without blink mechanisms or spell immunity will have a hard time positioning against Pit of Malice: Sven, Tiny, Wraith King, Dragon Knight, Meepo, Doom, Bounty Hunter, Dark Seer, Undying, Alchemist, Legion Commander.

* Arc Warden's Magnetic Field dodges all damage from Death Ward. Should he choose to buy a Necronomicon, they are quite effective to absorb some shots from your cask, and attack you during Death Ward.

* Ranged heroes will have a hard time hitting enemies inside Magnetic Field: Silencer, Viper.

* Ranged heroes will have a hard time hitting enemies inside Magnetic Field: Silencer, Viper.

* Arc Warden with his Magnetic Field will protect allies from Mass Serpent Ward.

* In general, melee heroes without blink mechanisms or spell immunity will have a hard time positioning against Pit of Malice: Sven, Tiny, Wraith King, Dragon Knight, Meepo, Doom, Bounty Hunter, Dark Seer, Undying, Alchemist, Legion Commander.

* Heroes with illusions can overwhelm Huskar, as he has no AoE abilities: Phantom Lancer, Anti-Mage, Arc Warden, Chaos Knight.

* In general, melee heroes without blink mechanisms or spell immunity will have a hard time positioning against Pit of Malice: Sven, Tiny, Wraith King, Dragon Knight, Meepo, Doom, Bounty Hunter, Dark Seer, Undying, Alchemist, Legion Commander.

* Arc Warden's Tempest Double is helpful for killing Ogre Magi who lacks AoE damage and disables.

* In general, melee heroes without blink mechanisms or spell immunity will have a hard time positioning against Pit of Malice: Sven, Tiny, Wraith King, Dragon Knight, Meepo, Doom, Bounty Hunter, Dark Seer, Undying, Alchemist, Legion Commander.

* In general, melee heroes without blink mechanisms or spell immunity will have a hard time positioning against Pit of Malice: Sven, Tiny, Wraith King, Dragon Knight, Meepo, Doom, Bounty Hunter, Dark Seer, Undying, Alchemist, Legion Commander.

* In general, melee heroes without blink mechanisms or spell immunity will have a hard time positioning against Pit of Malice: Sven, Tiny, Wraith King, Dragon Knight, Meepo, Doom, Bounty Hunter, Dark Seer, Undying, Alchemist, Legion Commander.

* Magnetic Field's evasion completely negates Sniper's attacks unless he has True Strike.
* Sniper always positions himself far away from battles, which makes him especially vulnerable for Flux and Spark Wraith.

* Heroes with powerful rooting abilities will disable most of Pangolier's skill, a bonus point if it pierce spell immunity since it will also be able to stop Pangolier during his Rolling Thunder: Treant Protector, Meepo, Crystal Maiden, Dark Willow, Underlord, Naga Siren

* Powerful physical hitters that can destroy Pangolier during his rolling from afar: Drow Ranger, Sniper, Templar Assassin, Arc Warden

* 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.

* In general, melee heroes without blink mechanisms or spell immunity will have a hard time positioning against Pit of Malice: Sven, Tiny, Wraith King, Dragon Knight, Meepo, Doom, Bounty Hunter, Dark Seer, Undying, Alchemist, Legion Commander.

* Firestorm will clear easily Chen's creeps.
* Pit of Malice will trap Chen and render him helpless.
* Atrophy Aura gives bonus damage to Underlord for each killed creep and weakens Chen's damage.
* Dark Rift can counter Chen's pushing attempts, and he has nothing to intercept it.

* Heroes who can slow and kite Axe will severely inhibit his presence in fights: Bristleback, Crystal Maiden, Batrider, Arc Warden, Winter Wyvern, Clockwerk

* In general, melee heroes without blink mechanisms or spell immunity will have a hard time positioning against Pit of Malice: Sven, Tiny, Wraith King, Dragon Knight, Meepo, Doom, Bounty Hunter, Dark Seer, Undying, Alchemist, Legion Commander.

* 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.