Dark Seer
* Dark Seer's strength lies in his high-mana cost skills. So 
Mana Break can be a great nuisance for him, since it can reduce his mana and prevent him from casting his spells.
* 
Mana Void can deal a lot of damage if Dark Seer spent a lot of mana on his abilities.
Dark Willow
* 
Counterspell negates Dark Willow's high magic burst damage. Its active blocks 
Cursed Crown.
* 
Blink allows Anti-Mage to dodge Terrorize during its long cast animation, as well as avoiding the obstacles from Bramble Maze. On the other hand, if Anti-Mage gets caught inside Bramble Maze, he's unable to Blink away.
* Dark Willow's chained magic burst requires a lot of mana, setting her up for damaging Mana Voids.
Dark Seer
* 
Flame Guard makes Dark Seer not deal any damage with his skills to Ember Spirit.
Dark Willow
* Flame Guard blocks Dark Willow's magical burst damage, and harms her if she tries to get close to attack with Bedlam.
* 
Sleight of Fist and 
Fire Remnant makes it hard for Dark Willow to fully disable Ember Spirit.
Dark Seer
* Abilities that deal low damage with high amounts of instances are irrelevant against Pudge during Flesh Heap's active: 
Gyrocopter's 
Rocket Barrage and 
Dark Seer's 
Ion Shell are just a couple examples.
Dark Willow
* 
Rot and 
Meat Hook hits Dark Willow even when she uses Shadow Realm.
* 
Flesh Heap reduces Dark Willow's magic burst damage.
Dark Seer
* Strong laners are usually at a disadvantage because of how well Sven can jungle. Heroes such as Dark Seer. 
Underlord and 
Legion Commander may find that later Sven takes care of them very quickly after some jungle farming.
Dark Willow
* Heroes with high burst damage and 
Black King Bar can take down Dark Willow quickly: 
Phantom Assassin, 
Sven, 
Wraith King
Dark Seer
* 
X Marks the Spot prevents Dark Seer or his allies from escaping with Surge.
Dark Willow
* 
Magnetic Field lets Arc Warden or allies evade Dark Willow's shadow realm attacks. The duration of the evasion can be extended with the clone.
* 
Spark Wraith also exploits Dark Willow's low mobility.
Dark Willow
* 
Blade Fury dispels most of Dark Willow's abilities, allowing Juggernaut to pass through Bramble Maze and cancel out Cursed Crown before the stun occurs.
* However, Dark Willow can tank 
Omnislash with 
Shadow Realm. As she is a valid target, but invulnerable to right clicks.
Additional:
* None of Dark Willow's spells pierce Spell Immunity, making Blade Fury a good counter against her. Additionally, it dispels Cursed Crown and 
Bramble Maze.
* Dark Willow is generally fragile, which results in Omnislash being devastating against her.
* However, if Shadow Realm is activated during Omnislash, then the attack damage is negated (though Omnislash can still jump to other enemies).
Dark Seer
* 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.
Dark Willow
* 
Last Word and 
Arcane Curse have the range to hit Dark Willow beyond Bramble Maze.
* 
Global Silence renders Dark Willow useless in teamfights.
Dark Willow
* 
Berserker's Call forces Dark Willow to attack, cancelling Shadow Realm.
Dark Willow
* 
Smoke Screen prevents Dark Willow from using her abilities, rendering her defenseless and unable to deal any serious damage.
* 
Blink Strike lets Riki jump past Bramble Maze.
Dark Willow
* 
Gust can hit Dark Willow beyond a defensive Bramble Maze, and before she gets close enough to hit Drow Ranger with Bedlam.
* Drow Ranger's long range allows her to hit Dark Willow's team without venturing into her Bramble Maze.
Dark Willow
* 
Ball Lightning allows Storm Spirit to bypass Bramble Maze into the backline, and zip back into battle if he gets hit by Terrorize.
Dark Willow
* 
Ancient Seal instantly shuts down Dark Willow's abilities, rendering her defenseless against his high burst damage spells, while she cannot cast spells of her own.
* 
Mystic Flare deals immense burst damage in an area, damaging Dark Willow through Shadow Realm.
Dark Willow
* All of Puck's abilities are area-targeted, and will hit Dark Willow when she uses Shadow Realm.
* 
Illusory Orb allows Puck to bypass Bramble Maze, close the gap and silence Dark Willow with 
Waning Rift.
* 
Phase Shift helps Puck dodge attacks charged by Shadow Realm, and is easily timed against Terrorize's long cast time.
Dark Willow
* Jakiro's area of effect abilities can hit Dark Willow even while she is hidden during the Shadow Realm.
* Waiting about 2 seconds after Dark Willow casts Shadow Realm to cast Ice Path will stun her while her Shadow Realm is at it's maximum damage.
* Jakiro can stun Dark Willow when there is about 1 second left on Cursed Crown, Jakiro's Ice Path stun lasts slightly longer then Cursed Crown.
Dark Seer
* A Sniper who is somewhat competent at positioning is hardly going to be affected by any of Dark Seer's spells thanks to 
Take Aim.
* However, an illusion of Sniper made with Wall of Replica is extremely powerful, and hard to deal with.
Dark Seer
* 
Spell Steal will easily steal all abilities from Dark Seer.
Additional:
* Spell Steal can perfect from Rubick's steal all abilities from Dark Seer. Rubick's always purchase 
Aghanim's Scepter can two stolens abilities from Dark Seer's and waiting for seconds for second stolen abilities (example: combinated Vacuum and Wall of Replica) and many different combination.
* A good positoning from Rubick's Spell Steal waiting steal abilities from Dark Seer 
Wall of Replica and illusion from Wall of Replica Dark Seer's can fighting with effect from outcome steal Wall of Replica from Rubick's.
* Combinated Rubick's steal Surge and 
Blink Dagger is very important catch from Dark Seer's and enemies.
* Rubick's 
Telekinesis can lifted up Dark Seer or enemy heroes and throw to Wall of Replica from Rubick's steal.
Dark Willow
* 
Quill Spray's constant AoE damage will hit Dark Willow even in Shadow Realm. Its automatic damage will hurt her if she tries to get close and use Bedlam.
Dark Seer
* Dark Seer's only disable is Vacuum. Though he starts off with high armor and health, he'll eventually have a hard time dealing with high mobility heroes such as 
Weaver or 
Queen of Pain.
Dark Seer
* Dark Seer relies on Surge for most of his mobility, so he's not very vulnerable to slows, but much more to root effects and walls or pseudo-walls such as 
Disruptor's 
Kinetic Field or 
Slark's 
Pounce.
Dark Willow
* Heroes who can silence will shut down Dark Willow entirely: 
Death Prophet, 
Silencer, 
Drow Ranger
Dark Seer
* Dark Seer's only disable is Vacuum. Though he starts off with high armor and health, he'll eventually have a hard time dealing with high mobility heroes such as Weaver or Queen of Pain.
Dark Willow
* 
Rage protects and dispels all of Dark Willow's abilities.
Additional:
* Rage protects Lifestealer from all of Dark Willow's abilities.
Dark Seer
* Heroes with escape abilities: 
Anti-Mage Dark Seer Slark 
Storm Spirit 
Windranger Weaver can kite Lifestealer due to him having no lockdown.
Dark Willow
* Nyx Assassin's high burst damage can be the bane of Dark Willow, as her low health makes it difficult to survive long enough to escape through Shadow Realm.
* 
Spiked Carapace can be triggered by walking deliberately into Bramble Maze, leaving Dark Willow stunned and defenseless.
Dark Seer
* Heroes who rely on damage over time as Spiked Carapace can block and reflect only one instance of damage: 
Jakiro, 
Viper, 
Venomancer, 
Huskar, 
Ember Spirit, Dark Seer, 
Sand King, 
Doom, 
Dawnbreaker. However, this also means they are easily stunned.
Dark Seer
* Dark Seer can take great advantage of 
Divided We Stand by putting an Ion Shell on a clone in order to harass them effectively.
* Vacuum can take a single Meepo and disable him for Dark Seer and his teammates to take out.
Dark Willow
* Casting Bramble Maze on top of Meepo guarantees a root, as it is nearly impossible to leave the thorns with all of Meepo's clones.
* Terrorize and Cursed Crown offer great disables against the grouped Meepos and can prevent them from using 
Poof to escape.
Dark Seer
* With 
Normal Punch from Aghanim's Scepter, Dark Seer can gain an advantage against heroes who rely on evasion as Normal Punch has true strike: Phantom Assassin, Windranger, 
Hoodwink.
Dark Willow
* 
Windrun does not protect Windranger from Cursed Crown's stun or Dark Willow's magical nukes.
* 
Focus Fire cannot target Dark Willow in Shadow Realm and will be interrupted if targeted earlier, wasting the ultimate.
Additional:
* Windrun does not protect Windranger from Cursed Crown stun or Dark Willow's magical nukes.
* Focus Fire cannot target Dark Willow in Shadow Realm and will be interrupted if targeted earlier, wasting the ultimate.
Dark Seer
* Certain heroes can mess up with Pangolier's positioning and timing (especially if he intends to use Rolling Thunder during combat): 
Vengeful Spirit, 
Keeper of the Light, Huskar, Dark Seer
Dark Willow
* Heroes with powerful rooting abilities will disable most of Pangolier's skills, a bonus point if it pierces 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
Dark Seer
* Dark Seer's 
Vacuum and Ion Shell can clear a wave of Chen's Creeps effectively.
* Surge applies haste movement and negates the slow from 
Penitence, allowing Dark Seer to easily escape from Chen and his creeps.
* Dark Seer's full combo from Dark Seer's Vacuum, Wall of Replica and Normal Punch from Aghanim's Scepter can often kill Chen or any of his allies before he can save them with 
Hand of God.
Additional:
* Dark Seer's Vacuum and Ion Shell can clear a wave of Chen's Creeps effectively.
* Surge applies haste movement and negates the slow from Penitence, allowing Dark Seer to easily escape from Chen and his creeps.
* Dark Seer's full combo from Dark Seer's Vacuum, Wall of Replica and Normal Punch from Aghanim's Scepter can often kill Chen or any of his allies before he can save them with Hand of God.
Dark Willow
* 
Terrorize, 
Bedlam and Cursed Crown can damage Muerta through 
Pierce the Veil.
* Even if Muerta has Black King Bar and Pierce the Veil active, Dark Willow can still use Shadow Realm to protect herself against the Pierce the Veil's high damage, as Muerta cannot attack her for it's duration.
Dark Seer
* Dark Seer's Vacuum and Ion Shell allows him to clear a wave of Terrorblade's illusions.
* Because Terrorblade often builds items that require 
Ultimate Orb like 
Manta Style and 
Eye of Skadi, Dark Seer can create a very strong illusion of Terrorblade with Wall of Replica and Normal Punch from Aghanim's Scepter.
* If Dark Seer can use Vacuum to help teammates land their AoE abilities, Terrorblade will be quickly killed before he even gets a chance to use Sunder.
Additional:
* Dark Seer's Vacuum and Ion Shell allows him to clear a wave of Terrorblade's illusions.
* Because Terrorblade often builds items that require Ultimate Orb like Manta Style and Eye of Skadi, Dark Seer can create a very strong illusion of Terrorblade with Wall of Replica and Normal Punch from Aghanim's Scepter.
* If Dark Seer can use Vacuum to help teammates land their AoE abilities, Terrorblade will be quickly killed before he even gets a chance to use Sunder.
Dark Willow
* Terrorize forces Faceless Void out of 
Chronosphere.
Dark Seer
* Ion Shell destroys 
Refraction's protection stacks in short time.
* Surge ignores the massive slow from 
Psionic Trap.
Dark Willow
* Dark Willow's burst damage and stun prevents Troll Warlord from approaching her until he has Black King Bar.
* Troll Warlord's lack of burst damage makes it hard for him to kill Dark Willow before she slips into Shadow Realm.
Dark Willow
* Bramble Maze prevents Timbersaw from 
Timber Chaining away without getting rooted.
* Cursed Crown can still catch Timbersaw if he Timber Chains away.
* 
Reactive Armor offers little protection against Dark Willow's high magical damage.
Dark Willow
* Bramble Maze stops 
Charge of Darkness in its tracks. Its very long duration means it can be used as an obstacle to block off an incoming Spirit Break during teamfights.
* Shadow Realm and Bedlam can be activated when Dark Willow sees Charge of Darkness coming, preventing Spirit Breaker from using 
Nether Strike after the initial stun.
Dark Seer
* Venomancer is a low health hero and low range hero who is easy to harass with Ion Shell on a creep in the early game.
* Venomancer depends entirely on all his slows to keep distance or chase, but since Surge ignores slows, it is nearly impossible for Venomancer to hunt or run away from Dark Seer or his surged teammates.
Dark Willow
* Bramble Maze will very likely catch Marci midair, disabling Marci's chasing/fleeing ability.
* Shadow Realm prevents Marci from bursting Willow down since she relies on physical attacks and unit target spells. With Aghanim's Scepter, Willow can hit Marci while Marci can't hit Willow.
* Bedlam and 
Eul's Scepter of Divinity allows Willow to manfight if Marci initiates with Rebound.
* Terrorize and Cursed Crown combo can waste Marci's ultimate for almost half of its duration.
Dark Seer
* Ion Shell zones out Broodmother in the laning phase, and can kill her spiderlings if used on one Spiderling in a group.
* Vacuum can pull Broodmother out of the treeline.
Additional:
* Ion Shell is a very powerful weapon against Broodmother's Spiderlings and makes her laning much harder.
Dark Seer
* 
Living Armor can be destroyed quickly with Ion Shell.
Dark Seer
* Heroes that rely on illusions typically spawn very strong illusions inside Dark Seer Wall of Replica that he can use against them or their team: 
Phantom Lancer, 
Chaos Knight, Naga Siren, 
Terrorblade.
Additional:
* Ion Shell helps taking down illusions quickly, making it easy to identify the real Phantom Lancer.
* Surge allows Dark Seer and his teammates to run away from Phantom Lancer, who relies on his 
Phantom Rush to chase enemies.
Dark Seer
* Heroes with haste can negate Enchant's slow: Weaver, Dark Seer, 
Lycan, 
Centaur Warrunner.
Dark Seer
* With Normal Punch from Aghanim's Scepter, Dark Seer can gain an advantage against heroes who rely on evasion as Normal Punch has true strike: Phantom Assassin, Windranger, Hoodwink.
Dark Seer
* Heroes that rely on summons will suffer against Ion Shell, which kills them very quickly: 
Beastmaster, 
Broodmother, 
Enigma, 
Nature's Prophet, 
Visage, 
Warlock, Wraith King.
Dark Willow
* Heroes with high magical or pure damage will bypass Bulwark: 
Timbersaw, Dark Willow, Enigma, 
Invoker, 
Pugna, 
Skywrath Mage, 
Tinker, 
Zeus, 
Oracle.
Dark Seer
* Heroes that rely on summons will suffer against Ion Shell, which kills them very quickly: Beastmaster, Broodmother, Enigma, Nature's Prophet, Visage, Warlock, Wraith King.
Dark Seer
* Heroes that rely on illusions typically spawn very strong illusions inside Dark Seer Wall of Replica that he can use against them or their team: Phantom Lancer, Chaos Knight, Naga Siren, Terrorblade.
Dark Seer
* Heroes that rely on illusions typically spawn very strong illusions inside Dark Seer Wall of Replica that he can use against them or their team: Phantom Lancer, Chaos Knight, Naga Siren, Terrorblade.
Dark Willow
* 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.
Dark Seer
* Dark Seer can increase the movement speed of allies with Surge, breaking Static Link.
Dark Seer
* Heroes with hastes: Dark Seer, Lycan
Dark Seer
* Dark Seer can pull together Spectre's illusions with Vacuum, and Wall of Replica creates an illusion of Spectre that deals massive damage.
Dark Seer
* Heroes who do not have nor rely on passive abilities make Nethertoxin much less effective: 
Clinkz, Pugna, Nature's Prophet, Dark Seer, Lycan, 
Tusk
Dark Seer
* Heroes that rely on summons will suffer against Ion Shell, which kills them very quickly: Beastmaster, Broodmother, Enigma, Nature's Prophet, Visage, Warlock, Wraith King.
Dark Seer
* Heroes that rely on summons will suffer against Ion Shell, which kills them very quickly: Beastmaster, Broodmother, Enigma, Nature's Prophet, Visage, Warlock, Wraith King.
Additional:
* Surge allows for Dark Seer and his allies to escape from Upheaval due to it ignoring any slow.
Dark Seer
* 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.
Dark Seer
* Heroes with strong area-of-effect damaging and/or disabling abilities will be able to intercept Underlord and his team when they exit from Fiend's Gate: 
Luna's Aghanim's Scepter upgraded 
Eclipse, Dawnbreaker's 
Solar Guardian, 
Axe's Berserker's Call, 
Mars's 
Arena of Blood, Jakiro's 
Macropyre, 
Dual Breath and 
Ice Path, Naga Siren's 
Song of the Siren, 
Razor's 
Eye of the Storm and 
Plasma Field, 
Lina's 
Light Strike Array, Broodmother's 
Spinner's Snare from Aghanim's Scepter, 
Elder Titan's 
Earth Splitter and 
Echo Stomp, Alchemist's 
Unstable Concoction and 
Acid Spray, Queen of Pain's 
Sonic Wave, Dark Seer's Wall of Replica and Vacuum, Venomancer's 
Noxious Plague and 
Poison Nova from Aghanim's Scepter, Oracle's 
Fortune's End and 
Rain of Destiny from 
Aghanim's Shard, 
Bloodseeker's 
Blood Rite, Enigma's 
Black Hole and 
Midnight Pulse, 
Shadow Fiend's 
Requiem of Souls, 
Batrider's Aghanim's Scepter upgraded 
Flaming Lasso, 
Firefly, 
Flamebreak and 
Sticky Napalm, 
Ancient Apparition's 
Ice Blast, Sand King's 
Epicenter, 
Sand Storm and 
Burrowstrike, Gyrocopter's 
Call Down, Ember Spirit's Sleight of Fist, Death Prophet's 
Exorcism and 
Silence, 
Monkey King's 
Wukong's Command, Crystal Maiden's 
Freezing Field, 
Muerta's 
The Calling, 
Medusa's 
Stone Gaze, Zeus's 
Nimbus from Aghanim's Scepter. Dark Willow's Bramble Maze, 
Pangolier's 
Swashbuckle, 
Grimstroke's 
Soulbind, 
Ink Swell and 
Stroke of Fate, 
Earthshaker's 
Echo Slam and 
Fissure, 
Puck's 
Dream Coil and Waning Rift, 
Winter Wyvern's 
Winter's Curse, 
Magnus's 
Reverse Polarity.
Dark Willow
* Heroes with strong area-of-effect damaging and/or disabling abilities will be able to intercept Underlord and his team when they exit from Fiend's Gate: Luna's Aghanim's Scepter upgraded Eclipse, Dawnbreaker's Solar Guardian, Axe's Berserker's Call, Mars's Arena of Blood, Jakiro's Macropyre, Dual Breath and Ice Path, Naga Siren's Song of the Siren, Razor's Eye of the Storm and Plasma Field, Lina's Light Strike Array, Broodmother's Spinner's Snare from Aghanim's Scepter, Elder Titan's Earth Splitter and Echo Stomp, Alchemist's Unstable Concoction and Acid Spray, Queen of Pain's Sonic Wave, Dark Seer's Wall of Replica and Vacuum, Venomancer's Noxious Plague and Poison Nova from Aghanim's Scepter, Oracle's Fortune's End and Rain of Destiny from Aghanim's Shard, Bloodseeker's Blood Rite, Enigma's Black Hole and Midnight Pulse, Shadow Fiend's Requiem of Souls, Batrider's Aghanim's Scepter upgraded Flaming Lasso, Firefly, Flamebreak and Sticky Napalm, Ancient Apparition's Ice Blast, Sand King's Epicenter, Sand Storm and Burrowstrike, Gyrocopter's Call Down, Ember Spirit's Sleight of Fist, Death Prophet's Exorcism and Silence, Monkey King's Wukong's Command, Crystal Maiden's Freezing Field, Muerta's The Calling, Medusa's Stone Gaze, Zeus's Nimbus from Aghanim's Scepter. Dark Willow's Bramble Maze, Pangolier's Swashbuckle, Grimstroke's Soulbind, Ink Swell and Stroke of Fate, Earthshaker's Echo Slam and Fissure, Puck's Dream Coil and Waning Rift, Winter Wyvern's Winter's Curse, Magnus's Reverse Polarity.
Dark Seer
* Heroes that rely on summons will suffer against Ion Shell, which kills them very quickly: Beastmaster, Broodmother, Enigma, Nature's Prophet, Visage, Warlock, Wraith King.
Dark Seer
* The haste provided by Dark Seer's Surge or a {Rune:Haste} renders Lich's slows ineffective.
Dark Seer
* In general, heroes who are melee with no way to fight back can be very easily poked by Monkey King to gain his Jingu Mastery stacks: Dark Seer, 
Riki, 
Rubick.
Dark Willow
* Terrorize forces Monkey King out of Wukong's Command.
Dark Seer
* Heroes with fast movement abilities will suffer huge damage when afflicted by Rupture: 
Spirit Breaker, 
Earth Spirit, Dark Seer.
Additional:
* 
Rupture can deal a lot of damage to either a surged Dark Seer or his allies and prevent the target from getting into position.
Dark Willow
* Bramble Maze greatly hinders Bloodseeker's ability to run around in teamfights and pick off dying allies.
* Shadow Realm prevents Bloodseeker from attacking dark Willow, allowing her to safely teleport away.
Dark Seer
* Dark Seer relies on Surge for most of his mobility, so he's not very vulnerable to slows, but much more to root effects and walls or pseudo-walls such as Disruptor's Kinetic Field or Slark's Pounce.
Dark Seer
* Heroes with AoE abilities will hit Slark in Shadow Dance: Lina, Jakiro, Underlord, 
Leshrac, Dark Seer, Earthshaker, Timbersaw, Crystal Maiden.
Dark Willow
* Heroes with high burst damage and Black King Bar can take down Dark Willow quickly: Phantom Assassin, Sven, Wraith King
Dark Seer
* With Normal Punch from Aghanim's Scepter, Dark Seer can gain an advantage against heroes who rely on evasion as Normal Punch has true strike: Phantom Assassin, Windranger, Hoodwink.
Dark Willow
* Heroes with high burst damage and Black King Bar can take down Dark Willow quickly: Phantom Assassin, Sven, Wraith King
Dark Seer
* Heroes that rely on summons will suffer against Ion Shell, which kills them very quickly: Beastmaster, Broodmother, Enigma, Nature's Prophet, Visage, Warlock, Wraith King.
Dark Seer
*
Fortune's End dispels Ion Shell and Surge, making any gank attempt on Dark Seer in the laning phase likely to succeed.
Fate's Edict prevents all magical damage that comes from Dark Seer's abilities. 
Fortune's End dispels Ion Shell on creeps, which Dark Seer relies on to farm and zone.
Ion Shell, a skill that helps Dark Seer immensely in the laning phase, as well as 
Surge, a move-speed buff, effectively allowing Oracle to control Dark Seer, especially in the laning phase.
*
*
Additional:
* Fortune's End can dispel
Dark Willow
*
Fortune's End not being disjointable is almost an ensured disable if Dark Willow tries to escape with Shadow Realm. Dispels Cursed Crown and Terrorize.
Fate's Edict negates all her magic damage in case she catches a single hero.
False Promise's strong dispel removes Dark Willow's disables.
Cursed Crown before it times out and stuns. He can also save a stunned ally with False Promise.
Bedlam's over-time damage, since the spell provides no form of control. Similarly, he can also negate the magic burst from 
Shadow Realm.
Terrorize, and it can remove the root from 
Bramble Maze if cast quick enough. Be mindful that Fortune's End only dispels your allies' debuffs on the primary target.
*
*
Additional:
* Fortune's End can easily dispel
* Fate's Edict can easily negate
* Fortune's End can dispel the fear effect from