Beastmaster
* Heroes with Linken's Sphere as core item: 
Weaver, 
Morphling, 
Medusa.
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.
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.
Beastmaster
* 
Cold Embrace mitigates Primal Roar's single-target initiation on allies.
* 
Winter's Curse can turn Beastmaster's summons and Inner Beast against his teammate.
Additional:
* Beastmaster's summons and 
Inner Beast are very useful to attack his cursed teammate.
* Cold Embrace effectively mitigates 
Primal Roar's single-target initiation on allies.
Beastmaster
* 
Reactive Armor is very effective against Beastmaster's summons during laning stage and entire game.
* Timbersaw can quickly clear Beastmaster's summons with his nukes.
* 
Lotus Orb item for Timbersaw can releases roar from the target position, stunning and damaging Beastmaster and knocking away, damaging and slowing allies that stand on the way.
Beastmaster
* 
Aphotic Shield effectively nullifies Primal Roar's single-target initiation on allies.
* Even being initiated by Primal Roar, 
Borrowed Time can make Abaddon extremely difficult to kill.
Additional:
* Primal Roar can be instantly dispelled by Aphotic Shield.
* The debuffs from 
Wild Axes and 
Poison from 
Call of the Wild: Boar can also be dispelled by Aphotic Shield.
Beastmaster
* 
Illuminate clears Beastmaster's summons and is effective against his push.
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
* 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
* 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.
Beastmaster
* Heroes with AoE abilities are a bane to Beastmaster's summons: 
Storm Spirit, 
Magnus, 
Pangolier.
Marci
* 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.
Additional:
* 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.
Beastmaster
* Heroes with other kind of disables that pierce spell immunity can hold Pangolier in place during Rolling Thunder: 
Axe, 
Beastmaster, 
Enigma, Magnus, 
Pudge, 
Batrider, 
Bane, 
Winter Wyvern
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.
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.
Beastmaster
* Having many summons out will cause 
Echo Slam to deal extra damage.
Marci
* 
Counterspell will reflects from Dispose. Counterspell timing well can not throw from Dispose endured position and Dispose will blocked.
Beastmaster
* 
Frostbite kills boars instantly on the laning stage leading to either experience lead or disabling Beastmaster from using Boar
* 
Crystal Nova nukes and slows down the attack and movement speed of Beastmaster's summons.
* 
Freezing Field grants improved self armor, nukes and slows down Beastmaster and his summons.
Beastmaster
* Heroes with Linken's Sphere as core item: Weaver, Morphling, Medusa.
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.
Beastmaster
* 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.
Beastmaster
* Heroes with strong dispels can remove Primal Roar's stun: 
Abaddon, 
Slark, 
Oracle.
Beastmaster
* Heroes with summoned units don't fare well against Dawnbreaker. (
Phantom Lancer ,Beastmaster ,
Lycan).
Beastmaster
* Heroes with AoE abilities are a bane to Beastmaster's summons: Storm Spirit, Magnus, Pangolier.
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.
Beastmaster
* Heroes who rely on high mobility are especially vulnerable to Primal Roar: Storm Spirit, Ember Spirit, 
Queen of Pain.
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 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 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 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.
Beastmaster
* Heroes who summon multiple units that are not spell immune. Nature's Prophet,Lycan,Beastmaster
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.
Beastmaster
* Heroes with AoE abilities are a bane to Beastmaster's summons: Storm Spirit, Magnus, Pangolier.
Beastmaster
* Heroes with Linken's Sphere as core item: Weaver, Morphling, Medusa.
Beastmaster
* Single-target disablers will have difficulty locking down a Chaos Knight with Phantasm active: Bane, Beastmaster, 
Bloodseeker, 
Clockwerk, 
Doom, Shadow Shaman.
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
* 
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.
Beastmaster
* Heroes with disables that go through spell immunity can end Bloodseeker before he has the chance to do anything: Batrider, Beastmaster
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.
Beastmaster
* Long lockdown is a great way to deal with Axe to prevent Berserker's Call from being used, heroes such as 
Legion Commander, Beastmaster and 
Primal Beast are good examples of this.
Beastmaster
* Inner Beast helps Beastmaster's team destroy 
Supernova quickly.
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.
Beastmaster
* Attacks from Boars and the attack speed boost from Inner Beast will quickly wear down 
Refraction.
Beastmaster
* Wild Axes, Primal Roar and 
Drums of Slom can deal high damage to Chen and clear waves of his creeps.
* Even though Chen can take control of the Boar from 
Call of the Wild Boar at any time with 
Holy Persuasion, which could put Beastmaster in a disadvantage against Chen. Skilled Beastmaster can buy 
Helm of the Overlord to regain control of it to counter this problem.
* Smart Beastmaster can also buy 
Bloodthorn to prevent Chen from taking control of the Boar from Call of the Wild Boar and make Chen more vulnerable to Beastmaster.
Beastmaster
* Wild Axes destroys large amounts of trees specially upgraded with Aghanim's Scepter,
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.
Beastmaster
* The Hawk can easily find Monkey King while he is sitting on a tree.
* Wild Axes can knock out Monkey King from tree.
* Boars drastically reduce Monkey King's attack speed, making it harder for him to gain 
Jingu Mastery stacks.
Additional:
* Wild Axes can chop down trees, making it difficult for Monkey King to utilize Tree Dance well.
* 
Call of the Wild Hawk can scout Monkey King when he is perched on top of trees.
* Primal Roar can stun Monkey King for a lengthy duration even with spell immunity.
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.
Beastmaster
* Wraith King's lack of area of effect spells makes him easily overwhelmed by Beastmaster's summons.
Beastmaster
* Primal Roar and the slow from Boars makes kiting Ursa very easy.
Marci
* 
Sprout can't stop her to Rebound.
* Treants can be used as targets for Rebound and Dispose as well.
Beastmaster
* Primal Roar and the slow from Boars make kiting Troll Warlord very easy.
Beastmaster
* Primal Roar and the slow from Boars make kiting Tiny very easy.
Beastmaster
* Beastmaster's Hawk can find Tinker easily while he is pushing or blinking into trees.
Beastmaster
* Illusion or summon-based heroes can be a problem to Viper due to his lack of AoE damage: 
Naga Siren, Phantom Lancer, Beastmaster
Beastmaster
* Heroes who relies on illusions and summons (Beastmaster, 
Chaos Knight, etc.).
Beastmaster
* Heroes who can stun Sven even with an activated Black King Bar can be an issue: Clockwerk, Beastmaster.
Additional:
* Primal Roar takes Sven out of the fight completely, even with Black King Bar.
Marci
* Marci can be effective against vulnerable squishy heroes that cannot deal with heroes that jump onto them - 
Sniper, 
Drow Ranger, 
Lina, Rubick, etc.
Beastmaster
* Skywrath Mage also has a terrible time fighting against anything that isn't a hero. His skills are mostly target-based and he has terrible strength and agility, he can easily be kited or harassed by illusion-based heroes like Chaos Knight and Phantom Lancer, or by Heroes that summon other units like 
Lone Druid, Lycan and Beastmaster.
Beastmaster
* Heroes who rely on high mobility are especially vulnerable to Primal Roar: Storm Spirit, Ember Spirit, Queen of Pain.
Beastmaster
* Heroes with illusions and summons can manfight Night Stalker: 
Terrorblade, Beastmaster, Broodmother.
Beastmaster
* Any long duration disables that can pierce through both, Pierce The Veil and Black King Bar are devastating against Muerta: Enigma's 
Black Hole, 
Dawnbreaker's 
Solar Guardian, Axe's Berserker's Call, Naga Siren's Aghanim's Scepter upgraded 
Ensnare and 
Reel In from Aghanim's Scepter, 
Jakiro's Aghanim's Scepter upgraded 
Macropyre, Bane's 
Fiend's Grip, Pudge's 
Dismember, Batrider's 
Flaming Lasso, Beastmaster's Primal Roar, 
Grimstroke's 
Soulbind, Medusa's 
Stone Gaze, Magnus's 
Reverse Polarity.
Beastmaster
* Because only one clone needs to be killed in order to kill Meepo, heroes that excel at singling out enemies can also be a detriment to him, such as Batrider, Beastmaster, Pudge and Clockwerk.
Marci
* Marci can be effective against vulnerable squishy heroes that cannot deal with heroes that jump onto them - Sniper, Drow Ranger, Lina, Rubick, etc.
Beastmaster
* Heroes with both illusions and summons, for Io has nothing to deal with multiple enemies at once outside from Spirits's weak area-of-effect: Beastmaster, Broodmother, Chaos Knight, Lycan, Naga Siren, Nature's Prophet, Phantom Lancer, Shadow Shaman, Terrorblade, Visage, Warlock, Wraith King.
Beastmaster
* Long ranged disables, especially those that pierce spell immunity, cancel Black Hole: Beastmaster's Primal Roar, Bane's Fiend's Grip, Faceless Void's 
Chronosphere, Magnus's Reverse Polarity, Axe's Berserker's Call, Pudge's
Meat Hook.
Marci
* Marci can be effective against vulnerable squishy heroes that cannot deal with heroes that jump onto them - Sniper, Drow Ranger, Lina, Rubick, etc.
Beastmaster
* Heroes with summons or illusions can counter Flux, such as Beastmaster , 
Chen, or 
Shadow Demon.
Beastmaster
* Heroes with disables that ignore spell immunity will render Phantom Assassin completely useless in teamfights throughout the game: Axe, Enigma, 
Vengeful Spirit, Doom, Bane, Beastmaster, Pudge, Medusa, Warlock.
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.
Beastmaster
* Heroes who rely on high mobility are especially vulnerable to Primal Roar: Storm Spirit, Ember Spirit, Queen of Pain.
Beastmaster
* 
Untouchable negates Inner Beast's attack speed bonus, making her hard to kill even if stunned by Primal Roar.
* Enchantress can also take control of Beastmaster's summons.
Additional:
* 
Enchant can control Beastmaster's boars with Enchant, mitigating his effectiveness during the laning stage and teamfights.
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.
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
* 
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.
Beastmaster
* Primal Roar allows Beastmaster to keep Lycan in place after he used his Shapeshift.
Beastmaster
*
False Promise effectively nullifies Primal Roar's single-target initiation on allies.
Purifying Flames kills Beastmaster's Hawk instantly and Boar with two casts.
*
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.
*
*