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.
Marci
* 
Counterspell will reflects from Dispose. Counterspell timing well can not throw from Dispose endured position and Dispose will blocked.
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.
Marci
* Rupture ruins her only movement ability, Rebound. Combined with its high movement speed and her being unable to interrupt it once its cast, using it under the effects of Rupture will surely deal incredibly immutable damage, if not kill her.
* As a Strength hero, Marci naturally has high HP. Rupture's initial damage uses her high HP as a catalyst to deal damage depending on her current health, dealing a good amount of damage if she's full HP or forcing her to stop if she's low.
* With 
Aghanim's Shard, 
Bloodrage will now deal pure damage and lifesteal based on the opponent's max health. Her high HP as a Strength hero ensures that Bloodseeker will always deal significant attack damage and sustain himself a lot whenever he attacks Marci.
* If Marci doesn't build 
Black King Bar, Bloodseeker's 
Blood Rite will prevent her from using all of her spells which she relies quite heavily on. Her only dispel is tied to Sidekick with level 25 left talent.
Dark Seer
* 
X Marks the Spot prevents Dark Seer or his allies from escaping with Surge.
Marci
* Heroes that can keep Marci for a long time in one place so she can't pursue her targets, like 
Bane, 
Lion, 
Shadow Shaman, 
Invoker, 
Disruptor and 
Kunkka.
Dark Seer
* 
Flame Guard makes Dark Seer not deal any damage with his skills to Ember Spirit.
Marci
* Heroes that can reliably kite out Dispose, Unleash and dodge Rebound, like 
Ember Spirit, 
Void Spirit, 
Storm Spirit, 
Anti-Mage, 
Faceless Void, 
Puck or always build items like 
Blink Dagger and 
Force Staff.
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.
Marci
* Marci's Dispose is blocked by 
Linken's Sphere which is a common item for Weaver.
* 
Shukuchi allows Weaver to escape from 
Rebound slow.
* 
The swarm beetle require 4 hits to kill. Weaver can use it on her when she use Unleash. This give Marci a hard choice: ignore The swarm and her armor keep decreasing or kill the beetle and wasting 4 attacks of Unleash.
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.
Marci
* Heroes that can keep Marci for a long time in one place so she can't pursue her targets, like Bane, Lion, Shadow Shaman, Invoker, Disruptor and Kunkka.
Marci
* Unleash ensures that Axe's 
Counter Helix procs many times, even if he is stunned by Dispose.
* Aghanim's Shard allows Counter Helix to reduce the attack damage of anyone it strikes. Combined with Unleash causing to proc frequently, Marci will not be dealing significant damage as she attacks Axe over time.
* Axe doesn't worry about the damage from Unleash if he activates 
Berserker's Call beforehand. If he had activated 
Blade Mail or 
Mjollnir (or even both) as Marci attacks him, he will turn Unleash's high attack speed and damage against her.
* Usually, Axe would prefer to jump on his opponent to be more effective. Rebound does Axe a favor, bringing Marci within his most effective range.
Marci
* 
Howl reduces a good chunk of Marci's attack damage that she relies heavily on, and the armor reduction works better on her because of her low armor.
* 
Shapeshift renders Lycan immune to slow from Rebound and Unleash.
Marci
* 
Death Pulse and 
Ghost Shroud very effective against her physical damage.
* 
Heartstopper Aura and 
Reaper's Scythe are very effective against tanky Strength hero Marci.
Marci
* 
Spirit Siphon exploits her naturally high HP to deal a good amount of DPS. She may break the link with Rebound, but 
Silence covers that problem.
* Marci's poor armor makes her vulnerable to 
Exorcism.
Marci
* 
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
* 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 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.
Marci
* Heroes that reduce the damage that Marci can deal during her ultimate, like 
Razor, 
Rubick, Bane, 
Dragon Knight and 
Underlord.
Marci
* Marci can be effective against vulnerable squishy heroes that cannot deal with heroes that jump onto them - 
Sniper, 
Drow Ranger, 
Lina, Rubick, etc.
Marci
* Heroes that can keep Marci for a long time in one place so she can't pursue her targets, like Bane, Lion, Shadow Shaman, Invoker, Disruptor and Kunkka.
Additional:
* Shadow Shaman can provide an excellent counter-initiation against her Rebound. His abilities can shut down any of her tower dive attempts in the laning phase.
* Shackles keeps Marci stunned for an extended time, wasting her ultimate. A combo with Mass Serpent Ward only makes things worse for her, as her armor is low.
Marci
* Heroes that can keep Marci for a long time in one place so she can't pursue her targets, like Bane, Lion, Shadow Shaman, Invoker, Disruptor and Kunkka.
Marci
* Heroes that can keep Marci for a long time in one place so she can't pursue her targets, like Bane, Lion, Shadow Shaman, Invoker, Disruptor and Kunkka.
Marci
* Heroes that can reliably kite out Dispose, Unleash and dodge Rebound, like Ember Spirit, Void Spirit, Storm Spirit, Anti-Mage, Faceless Void, Puck or always build items like Blink Dagger and Force Staff.
Marci
* Heroes that can keep Marci for a long time in one place so she can't pursue her targets, like Bane, Lion, Shadow Shaman, Invoker, Disruptor and Kunkka.
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 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.
Marci
* Heroes that can reliably kite out Dispose, Unleash and dodge Rebound, like Ember Spirit, Void Spirit, Storm Spirit, Anti-Mage, Faceless Void, Puck or always build items like Blink Dagger and Force Staff.
Marci
* Heroes that reduce the damage that Marci can deal during her ultimate, like Razor, Rubick, Bane, Dragon Knight and Underlord.
Marci
* Heroes that can reliably kite out Dispose, Unleash and dodge Rebound, like Ember Spirit, Void Spirit, Storm Spirit, Anti-Mage, Faceless Void, Puck or always build items like Blink Dagger and Force Staff.
Marci
* Heroes that can reliably kite out Dispose, Unleash and dodge Rebound, like Ember Spirit, Void Spirit, Storm Spirit, Anti-Mage, Faceless Void, Puck or always build items like Blink Dagger and Force Staff.
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 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 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.
Marci
* Heroes that reduce the damage that Marci can deal during her ultimate, like Razor, Rubick, Bane, Dragon Knight and Underlord.
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.
Marci
* Lifestealer's 
Rage renders him immune to all of Marci's disables and magic damage for a good duration.
* His passive 
Feast deals bonus damage based on the enemy's max health and heals for the same amount. As a tanky Strength hero, Marci's own strength will be her undoing as well.
Dark Seer
* Heroes with escape abilities: Anti-Mage Dark Seer Slark Storm Spirit 
Windranger Weaver can kite Lifestealer due to him having no lockdown.
Marci
* Warlock has strong counter initiation which reduces Marci's effectiveness throughout the game.
* 
Fatal Bonds cancels Blink Dagger, which means Marci can move in and out of fights less effectively.
* 
Chaotic Offering paired with 
Upheaval provides a ministun, a movement slow and paired with Fatal Bonds has the potential to deal a lot of damage to Marci while she jumps on a target. The ministun also means that Marci will have a harder time casting Rebound. If Warlock does build Aghanim's Scepter and 
Refresher Orb, the physical damage from Golems will overwhelm Marci, especially when played as a support.
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
* 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.
Marci
* Marci can be effective against vulnerable squishy heroes that cannot deal with heroes that jump onto them - Sniper, Drow Ranger, Lina, Rubick, etc.
Marci
* Pangolier's 
Lucky shot disarms her if procs making Unleash useless.
* Swashbuckle have a lower cooldown than Rebound so Pangolier can out maneuver her quite easily.
Additional:
* Pangolier's Lucky Shot disarms her if it procs, making 
Unleash useless.
* Swashbuckle will easily burn away Marci's already low mana pool with 
Diffusal Blade, an item commonly built on Pangolier.
* Swashbuckle's cooldown is shorter than Rebound, making it easy for Pangolier to outmaneuver her.
* Marci will get stunned if she tries to use Rebound while Pangolier is using Rolling Thunder, somewhat hindering her mobility in teamfights.
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 Seer
* Heroes with haste can negate Enchant's slow: Weaver, Dark Seer, 
Lycan, 
Centaur Warrunner.
Marci
* 
Untouchable doesn't work against Unleash, as Marci gains 1000+ attack speed for the fury combo.
* Enchantress' low health makes her a fragile target for Marci's damage blasts.
* Marci can use Rebound on one of her enchanted creeps to easily reach the Enchantress and negate the bonus damage dealt by her 
Impetus. It helps that most of her best creeps have a low attack range, creating a makeshift bridge towards their master.
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.
Marci
* 
Sprout can't stop her to Rebound.
* Treants can be used as targets for Rebound and Dispose as well.
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.
Marci
* Rebound allows her to jump in or out of the Arena Of Blood. She can save her allies from the Arena with Dispose as well.
Dark Seer
* 
Living Armor can be destroyed quickly with Ion Shell.
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 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.
Marci
* Marci on the midlane will win the laning phase against Zeus almost every time, as her powerspike at level 6 will decimate Zeus' low health pool and force him to stay far back.
* Even before level 6, Dispose and Sidekick can easily take half of Zeus' health if he is in range of Dispose.
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
* Ion Shell destroys 
Refraction's protection stacks in short time.
* Surge ignores the massive slow from 
Psionic Trap.
Marci
* Marci can destroy 
Supernova by herself with Unleash at any stage of the game.
* Phoenix is squishy hero with low armor and is very vulnerable for Rebound and Sidekick at the laning stage.
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 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.
Marci
* Marci can be effective against vulnerable squishy heroes that cannot deal with heroes that jump onto them - Sniper, Drow Ranger, Lina, Rubick, etc.
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 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
* 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 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
* 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 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
* The haste provided by Dark Seer's Surge or a {Rune:Haste} renders Lich's slows ineffective.
Dark Seer
* Heroes with hastes: Dark Seer, Lycan
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
* Dark Seer can pull together Spectre's illusions with Vacuum, and Wall of Replica creates an illusion of Spectre that deals massive damage.
Marci
* Marci can be effective against vulnerable squishy heroes that cannot deal with heroes that jump onto them - Sniper, Drow Ranger, Lina, Rubick, etc.
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
* 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.
Marci
* Heroes that reduce the damage that Marci can deal during her ultimate, like Razor, Rubick, Bane, Dragon Knight and Underlord.
Dark Seer
* Dark Seer can increase the movement speed of allies with Surge, breaking Static Link.
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 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
Marci
*
Fortune's End dispells Marci's 
Sidekick, removing additional damage and lifesteal.
Fate's Edict disarms Marci, preventing her from attacking with 
Unleash. Also it is useful against Marci or her ally affected by 
Sidekick.
False Promise is a great tool to save an ally focused by Marci.
*
*