Zeus
* Chaos Knight's high health pool makes him resistant to Zeus' burst damage. 
Phantasm can dispel 
Veil of Discord, a typical item purchased by Zeus.
* Zeus is easily overwhelmed by Chaos Knight's strong illusions, as Arc Lightning is not enough to kill them fast enough to have any impact.
* Zeus' low base armor makes him extremely vulnerable to Chaos Knight's high damage output and armor reduction.
Slark
* 
Dark Pact is minimally effective against Phantasm illusions, and Slark lacks area damage otherwise.
* 
Pounce can be counteracted by Reality Rift.
* Slark is naturally frail and dies quickly to Chaos Knight's burst damage before he can build 
Essence Shift stacks.
* Be aware, however, that 
Shadow Dance can make Slark hard to kill as he can't be targeted during its duration.
Additional:
* Phantasms have enough health to survive Dark Pact, and Slark has no other source of AoE damage to deal with them.
Zeus
* Heroes with low mobility that rely on spells: 
Zeus, 
Lina, 
Crystal Maiden.
Slark
* With Dark Ascension he can keep vision on Slark, disabling his Shadow Dance regeneration.
* Night Stalker is very fast so without the Pounce in lane, he can simply out distance him during the night.
* Slark is matched in night vision by only a few heroes, Night Stalker happens to be one of them.
Zeus
* As a spellcaster, silences will nullify him entirely. Some notable examples are 
Death Prophet, 
Drow Ranger, 
Bloodseeker, 
Disruptor and many others.
* 
Doom, as usual, fits this description nicely.
Slark
* Bloodseeker is one of the hardest counters to Slark.Thirst prevents Slark from healing in lane with Shadow Dance and may set him up for a kill while in the jungle,or retreating.
* Rupture will deal damage during Pounce.
* Dark Pact cannot dispel Rupture, preventing Slark from escaping ganks.
Additional:
* 
Thirst stops Shadow Dance's passive health regeneration if Slark's current health is below the Thirst's visibility threshold.
* 
Rupture effectively diminishes Slark's mobility in battle, leaving him susceptible to AoE stuns or forcing to teleport out of the fight.
Zeus
* Thundergod's Wrath strikes only the first Meepo.
* Zeus has low mobilty so consecutive 
Earthbinds are easy to hit and he'll quickly die from 
Poofs.
Slark
* 
Slark's Dark Pact and Pounce can deny only one Earthbind and Poof can penetrate Shadow Dance if he doesn't build Black King Bar.
Additional:
* Earthbind and Poof will still hit Slark in Shadow Dance.
* Dark Pact can only remove one Earthbind.
* 
Ransack will still affect Slark, even if he has a 
Black King Bar.
Zeus
* 
Corrosive Skin severely reduces Zeus's damage output throughout the game.
* During the laning stage, Viper can abuse Zeus' reliance on spells by hugging the creep wave. Zeus will take constant damage over time from Corrosive Skin unless he drives Viper from the lane or returns to farming in his absence.
* Prior to buying 
Blink Dagger or 
Force Staff, Zeus is fragile and possesses low mobility. Any of Viper's numerous slows can set up an easy kill.
Additional:
* Corrosive Skin counters Zeus in lane by canceling the effects of 
Clarity as Zeus relies on Arc Lightning to farm and secure last hits.
* Corrosive Skin also increases Viper's magic resistance to shrug off Zeus's magical nukes.
* 
Nethertoxin breaks Static Field.
* Due to Zeus' poor mobility, 
Viper Strike will cripple Zeus and will allow Viper and his teammates to land a lot of attacks.
Slark
* Heroes with Break abilities will prevent Slark from regenerating and gaining Essence Shift stacks: 
Viper, 
Shadow Demon, etc.
Additional:
* Viper Strike can disable Essence Shift and the regeneration aspect of Shadow Dance.
* Dark Pact doesn't mean a lot against Viper's ubiquitous slows.
* Viper becomes a relevant presence in team fights before Slark can procure his standard items (e.g. 
Shadow Blade).
Zeus
* As a spellcaster, silences will nullify him entirely. Some notable examples are Death Prophet, Drow Ranger, Bloodseeker, Disruptor and many others.
* Doom, as usual, fits this description nicely.
Slark
* Thunder Strike provides vision on him while Slark is invisible.
* Glimpse's range at lvl 3-4 is more than enough to pull him back to a favorable position for your team to group up and kill him.
* Even though he is capable of picking you off and deal enough damage to kill you, Slark will be literally sticking his neck out, since jumping on Disruptor means being on his battleground.
* AoE silence and the ability to mute Black King Bar is deadly to Slark at all stages of the game.
Additional:
* 
Static Storm and 
Kinetic Field locks down Slark, as he cannot use Dark Pact to dispel any disables, or Pounce out while silenced.
* 
Glimpse puts an end to any attempts at ganking Disruptor or his allies, and also negates Slark's mobility by bringing him back into the fight if he tries to escape with Pounce.
Zeus
* 
Time Dilation can limit Zeus to casting his abilities only once in a fight, effectively serving as a 6/8/10/12 second silence.
* 
Time Walk negates Zeus's burst damage.
* 
Chronosphere makes Zeus the best target for Void because of his low mobility.
Slark
* Time Dilation while Dark Pact and Pounce are on cooldown will make these abilities unusable for a long time, reducing his escape potential. However, Time Dilation is dispellable with Dark Pact so it needs to be timed well.
* Chronosphere will not reveal Slark during Shadow Dance but covers the whole duration of Shadow Dance making him unable to use it to attack or escape. Slark still receives the regeneration benefit from Shadow Dance.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: 
Anti-Mage, 
Earth Spirit, 
Faceless Void, 
Magnus, 
Mirana, 
Monkey King, 
Morphling, 
Pangolier, 
Phantom Assassin, 
Phoenix, 
Puck, 
Queen of Pain, 
Riki, 
Sand King, 
Spirit Breaker, 
Timbersaw, 
Tusk.
Zeus
* Spirit Siphon does a lot of magical damage, especially in the early game. This allows her to demolish low health heroes such as Zeus, 
Pugna, especially when combined with her other spells.
Slark
* Heroes with silencing abilities can be particularly deadly when Slark is trying to escape: 
Silencer, Death Prophet, Puck, 
Doom.
Zeus
* Heroes who cannot prevent Sven from killing supports will always be at a disadvantage in fights such as Lina, Slark and Zeus.
Slark
* Heroes who cannot prevent Sven from killing supports will always be at a disadvantage in fights such as Lina, Slark and Zeus.
Slark
* Natural Order aura prevents Slark from gaining armor from the agility stolen with Essence Shift.
* Echo Stomp and Earth Splitter can hit Slark through his Shadow Dance ultimate.
* Slark's stats gain is relatively low compared to most agility carries making him quite squishy without his agility-based armor.
Slark
* Slark's dependence on Pounce and close range makes him very easy to hit with 
Purification and 
Hammer of Purity.
* Slark's damage, even with a high count of Essence Shift stacks, is easily negated by Omniknight's heals and 
Guardian Angel.
Zeus
* 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.
Slark
* Outworld Destroyer can disrupt Slark's attacks with 
Astral Imprisonment either by banishing Slark or his target.
* Slark's low heathpool means he will die quickly to 
Arcane Orb if he is directly attacked by Outworld Destroyer
* Slark has low intelligence gain, making him easy to finish with 
Sanity's Eclipse if he tries to run with Shadow Dance
Additional:
* Arcane Orb deals pure damage, which ignores the armor granted from permanent agility stacks.
* Astral Imprisonment can disrupt any Pounce attempt by banishing the leashed ally.
* Slark's low mana pool makes him more susceptible to Sanity's Eclipse.
Slark
* Berseker's Call catches Slark in Shadow Dance, wasting its duration and preventing him from escaping to regenerate.
* Unlike most disables, Dark Pact cannot dispel Berserker's Call and the output damage would be returned by 
Blade Mail.
Additional:
* 
Berserker's Call forces Slark to attack him, even during Shadow Dance.
* 
Counter Helix will hit Slark in Shadow Dance. It will also trigger frequently against Slark's high attack speed provided by Essence Shift stacks.
* 
Culling Blade finishes off Slark before he gets a chance to slip away and regenerate his health, preventing him from playing his typical hit-and-run style.
Zeus
* Huskar's Burning Spears chip through his low health pool quickly.Consequently, he is forced to either invest on health regen or abandon the lane.
* Reliant on magic damage, there is little he can do against Huskar.
* Huskar will usually kill him if he gets Life Break off,given Zeus' poor mobility.
Zeus
* Heroes with long range abilities are also able to touch Zeus, such as 
Clockwerk, 
Kunkka, Puck, 
Skywrath Mage, Spirit Breaker, Tusk and others.
Slark
* 
Illusory Orb and 
Phase Shift allows Puck to avoid most ganking attempts.
* 
Waning Rift and 
Dream Coil makes it very hard for Slark to escape bad situations.
* Puck's abilities used together also deals significant magical nuke damage, none of which are targeted and thus cannot be avoided by Shadow Dance.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Slark
* Though Slark's large damage output is most certainly a concern for the squishy Crystal Maiden, she does perform fairly well against him when coupled with aid from her team.
* Slark has no innate way to cancel Freezing Field, but the common purchase of 
Skull Basher does make Slark a substantially greater threat to Crystal Maiden as the game progresses.
* Freezing Field can still hit Slark while he is under the effect of Shadow Dance, and for the early and mid game, the damage output of Crystal Maiden's ultimate outscales Slark's passive regeneration, making a quick use of Freezing Field as soon as Slark uses Shadow Dance a great way to combat him.
* Crystal Maiden's Frostbite and Crystal Nova are helpful in disabling and slowing the slippery Slark so he can be killed by her teammates.
Slark
* Dark Pact, Shadow Dance and 
Depth Shroud will do nothing against Onslaught and Trample, as they are both ground area-of-effect spells.
* Primal Beast has a gigantic hitbox, which could be difficult for Slark to escape with Pounce should Primal Beast choose to block him. Pounce also does not completely prevent Primal Beast from trampling offensively, as he still has some room to move.
* Primal Beast has a huge health pool making it difficult to shed it with Essence Shift and may allow Primal Beast to build Uproar stacks against him very rapidly.
* If Primal Beast buys an 
Aghanim's Scepter he can also break Essence Shift from working on attacks which is a big part of Slark's damage output.
Zeus
* Zeus laneing against Ember is going to be punished with Sleight of Fist due to his low health pool
* Zeus's chip damage from 
Arc Lightning and other spells is nullified from Ember's Flame Guard.
Additional:
* Ember Spirit has a built-in antimagic shield, and Zeus has nothing but this magical damage, because of this, their confrontation on the center line can turn out to be sad for Zeus. If on such a line Ember Spirit will finish off all creeps under its 
Flame Guard, and Zeus with the help of Arc Lightning, then eventually Zeus will lose mana faster, and will be forced to look for ways to replenish it
* Ember Spirit can interrupt Zeus with his "jumping" abilities, the fact is that Zeus deals damage from his abilities directly, while Ember Spirit disappears for milliseconds from the battlefield when flying during the 
Sleight of Fist action or when flying into 
Fire Remnant
Slark
* 
Toss and 
Avalanche deals heavy damage to Slark in the early game, making Tiny a very dangerous target to gank.
* Tiny has 0 agility, which means Slark's Essence Shift permanent agility steal does not do much against him.
Slark
* Heroes that can deny Slark early kills will prevent him from snowballing: 
Dazzle, 
Abaddon.
Zeus
* Visage can quickly kill heroes with low to medium base armor and no innate escape mechanism. Examples include 
Alchemist, Crystal Maiden and Zeus.
Zeus
* Heroes with long range abilities are also able to touch Zeus, such as Clockwerk, Kunkka, Puck, Skywrath Mage, Spirit Breaker, Tusk and others.
Slark
* Heroes like Slark, 
Witch Doctor and others also tend to suffer in Ice Blast's heal denial.
Additional:
* 
Ice Blast stops Shadow Dance's passive health regeneration, even when Slark is not in vision.
Slark
* 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.
Zeus
* Zeus' main source of damage is his low cooldown, high damage spells - meaning Last Word and Global Silence will pretty much take him out of the game for the duration.
* Zeus likes to spam his abilities, which makes him vulnerable to Arcane Curse.
* If Zeus dies near Silencer, he will begin to lose intelligence, reducing his mana pool, mana regen, and attack damage. Furthermore, if the game is long and Zeus dies often, the intelligence losses will also reduce his spell damage.
Additional:
* Silencer's 
Global Silence will render Zeus useless for 6 seconds in a team fight.
* 
Arcane Curse will punish Zeus for casting spells, which can cause continuous damage to him should he continue to cast spells.
* 
Last Word can silence Zeus and prevent him from spamming his spells.
* Silencer often builds 
Orchid Malevolence (or 
Bloodthorn) which can be used on spell casters like Zeus, forcing him to invest in a 
Linken's Sphere.
Slark
* Heroes with silencing abilities can be particularly deadly when Slark is trying to escape: Silencer, Death Prophet, Puck, Doom.
Slark
* Slark's Dark Pact allows him to dispel Silencer's debuffs.
* Against a carry Silencer, Essence Shift will lower damage from both Glaives of Wisdom and his basic attack.
Zeus
* Heroes with long range abilities are also able to touch Zeus, such as Clockwerk, Kunkka, Puck, Skywrath Mage, Spirit Breaker, Tusk and others.
Slark
* Heroes with AoE abilities will hit Slark in Shadow Dance: Lina, 
Jakiro, 
Underlord, 
Leshrac, 
Dark Seer, 
Earthshaker, Timbersaw, Crystal Maiden.
Slark
* Heroes with AoE abilities will hit Slark in Shadow Dance: Lina, Jakiro, Underlord, Leshrac, Dark Seer, Earthshaker, Timbersaw, Crystal Maiden.
Zeus
* Zeus almost exclusively relies on magical damage, which is heavily reduced by Counterspell.
* Zeus' complete lack of mobility makes him very easy for Anti-Mage to chase down with Blink.
* Zeus likes to stand in the back during team fights, but Anti-Mage can easily Blink to close the distance.
Additional:
* Anti-Mage can burn mana, which is a big problem for a spellcaster like Zeus that heavily relies on it.
* 
Counterspell decreases magical damage taken from Zeus.
* Zeus' high intelligence and mana pool makes him a perfect target for 
Mana Void.
Slark
* Heroes who build mana boosting items but have low mana regeneration are especially vulnerable against Mana Break and Mana Void: Timbersaw, Slark, 
Shadow Fiend, 
Clinkz, Bristleback 
Nyx Assassin, Magnus
Slark
* Pounce prevents Anti-Mage from using Blink, and lets him disengage from Anti-Mage if needed.
* Essence Shift allows Slark to permanently steal agility from Anti-Mage.
* Shadow Dance stops Anti-Mage from being able to fight back in a slippery situation.
Zeus
* Heroes with summons that are destroyed by a fixed number of attacks: 
Undying's 
Tombstone, 
Gyrocopter's 
Homing Missile, and Zeus's 
Nimbus.
Slark
* Heroes with silencing abilities can be particularly deadly when Slark is trying to escape: Silencer, Death Prophet, Puck, Doom.
Zeus
* None of Zeus's abilities can damage a Juggernaut in 
Blade Fury.
* Zeus's short attack range makes it difficult for him to target a well-placed 
Healing Ward. His frequent use of Arc Lightning will have almost no effect on allies being healed by Juggernaut.
* Zeus has no way to defend himself, even if Juggernaut cannot use Blade Fury. He can be easily taken out if cornered, sometimes even without 
Omnislash.
Additional:
* Blade Fury negates all magical damage from Zeus.
* Omnislash can easily take down Zeus. However, be aware that most players will get a 
Eul's Scepter of Divinity or a 
Ghost Scepter against Juggernaut.
Slark
* Heroes with escaping and disjointing abilities can be good against Juggernaut:Anti-Mage Riki, Queen of Pain, Puck, 
Storm Spirit, 
Ember Spirit, Slark etc.
Additional:
* Blade Fury does not offer any protections against Essence Shift, as it can go through spell immunity and reduces attribute.
* Slark can pounce away from Juggernaut and he cannot prevent or chase slark.
* Shadow Dance prevent Juggernaut from using Omnislash altogether, while regen himself at a higher rate. Slark can freely hit juggernaut without any fears of retaliation.
Slark
* Both Scream of Pain and Sonic Wave should hit Slark during his Shadow Dance.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Slark
* 
Phantom's Embrace cannot be dispelled by Slark's Dark Pact, and will cause him to suffer damage if he doesn't kill Phantom fast enough.
* 
Soulbind also cannot be dispelled by Slark's Dark Pact, and will cause Slark to suffer from a single-targeted ability used on his ally that is also affected by it.
Zeus
* Heroes with powerful spammable abilities will prove problematic for Grimstroke as Ink Swell does not protect him from them: Zeus, Skywrath Mage, 
Tinker, Lina
Slark
* Slark has no sustained AoE to fight off Phantom Lancer's illusions as they continually spawn.
* Spirit Lance can give vision of Slark by spawning an illusion, making it harder for him to juke and gain the passive bonus from Shadow Dance.
* 
Phantom Rush helps Phantom Lancer chase down Slark if he tries to escape with Pounce.
Additional:
* Slark has no sustained AoE damage to deal with a lot of Phantom Lancer's illusions.
* 
Doppelganger lets Phantom Lancer dodge Dark Pact and Pounce and partially wastes the duration of Shadow Dance.
* 
Spirit Lance can give vision of Slark via spawning an illusion, making it harder for him to juke and gain the passive bonus from Shadow Dance.
* Phantom Rush helps Phantom Lancer chase down Slark when he jumps away with Pounce.
Zeus
* Heroes with global nukes will target and hit Phantom Lancer regardless of his illusions: Zeus
Zeus
* Heroes that depend on disrupting fights with ability combos or big ultimate abilities are vulnerable to the long stun of Fiend's Grip: Disruptor, Death Prophet, 
Enigma, Faceless Void, 
Invoker, 
Lich, Magnus, 
Mars, 
Medusa, 
Outworld Destroyer, Phoenix, Puck, Queen of Pain, Shadow Fiend, 
Treant Protector, Underlord, 
Winter Wyvern, Witch Doctor, Zeus.
Slark
* Low-health, normally mobile carries who rely entirely on raw attack damage are vulnerable to Bane's nukes and disables: Anti-Mage, Clinkz, Drow Ranger, Faceless Void, Gyrocopter, 
Juggernaut, 
Meepo, Mirana, Monkey King, Morphling, Phantom Assassin, Phantom Lancer, Riki, Shadow Fiend, Slark, 
Sniper, 
Terrorblade, 
Troll Warlord, 
Weaver.
Slark
* Dark Pact can dispel Enfeeble, as well as Nightmare and Fiend's Grip when timed correctly.
* Shadow Dance can protect Slark from Bane's single-target abilities.
Zeus
* Zeus can deal a huge amount of damage, but he lacks defensive abilities, such as good mobility or resistance. Due to that, he doesn't like to be touched by any means. Heroes with higher damage output and good mobility will often get easily near Zeus and trade damage (eventually causing Zeus's downfall). Such Heroes include: 
Lycan, Slark, Storm Spirit, Spectre and others.
Slark
* Heroes that rely on their high mobility such as Queen of Pain, Slark and Weaver can be constantly engaged against due to your excellent ability to chase over any terrain. Make sure you carry true sight items (such as 
Dust of Appearance or 
Gem of True Sight) for invisible heroes that could potentially escape your clutches.
Slark
* Pounce's leash prevents Storm Spirit from using 
Ball Lightning, making it hard for Storm Spirit to escape a gank from Slark.
* Dark Pact can dispel Orchid Malevolence's Soul Burn.
Zeus
* Due to Hoodwink's low health and Zeus's high magic damage from Arc Lightning, 
Lightning Bolt and 
Static Field as well as global abilities from 
Thundergod's Wrath and Nimbus, he can easily kill her throughout the game and also reveal where Hoodwink is positioned or when she's in trees.
Slark
* Slark's Pounce can be used to dodge Hoodwink's abilities or lock her down.
* Shadow Dance makes Slark unhittable from 
Acorn Shot.
* Dark Pact removes all slows from Hoodwink's abilities.
* Hoodwink's already low health output is a great target for Slark's Essence Shift.
Zeus
* Zeus can easily reveal Tinker's location in the trees with Thundergod's wrath.
* When Zeus has an Aghanim's Scepter, he can use his Nimbus, together with Lightning Bolt to interrupt Tinker's 
Keen Conveyance channelling and cancel Tinker's Blink Dagger.
Additional:
* Due to Tinker's low health pool, Zeus can easily burst Tinker down, while also cancelling 
Rearm.
* Once Zeus gets Aghanim's Scepter, he will gain Nimbus, which allows him to scout out Tinker on the map, especially when he is pushing lanes while hiding in the trees.
Slark
* Pounce prevents Tinker from blinking away.
* Slark frequently builds Shadow Blade, which allows him to approach Tinker unnoticed. Since Tinker's farming usually covers a significant amount of area on the map, Sentry Wards may not be cost effective.
* Shadow Dance allows Slark to detect both common and unusual wards. Eliminating common ward causes Tinker trouble farming many lanes if he does not know who may be waiting to jump on him. Slark is also uniquely able to identify some of the less common wards used by Tinker, such as those placed on the cliffs at map edges which Tinker uses to give him vision over the trees he uses to hide in.
* Slark's extremely high move speed from Shadow Dance, potentially stacked with Shadow Blade, allows him to easily follow Tinker between lanes, especially if Tinker has pushed the lanes out.
* Dark Pact dispels Laser's blind.
Zeus
* Zeus is good against heroes that juke in trees or up cliffs, like 
Batrider, Monkey King, Spectre, and Tinker, by providing vision in any area with Lightning Bolt, or guaranteeing vision on enemies with Thundergod's Wrath.
Slark
* Dark Pact can dispel Flaming Lasso if is used in anticipation, but a Blink initiation from fog can catch the Slark off guard.
* Slark can also take off any Sticky Napalm stacks with Dark Pact in lane.
Additional:
* Shadow Dance's passive can inform Slark when he's under enemy vision, meaning it'll be very hard to catch Slark off-guard with 
Flaming Lasso.
* Flaming Lasso is dispelled by Dark Pact. Its casting can be prevented with Shadow Dance or Depth Shroud (it requires 
Aghanim's Shard).
Zeus
* Heroes with spells that negate invisibility such as 
Bounty Hunter, Zeus and 
Slardar prevent her from saving her allies with Moonlight Shadow.
Slark
* If Slark sees the Sacred Arrow before it hits him, he can use Dark Pact to remove it a moment later.
* Pounce prevents Mirana from escaping with Leap.
* Slark can survive Mirana's Aghanim's Scepter​ combo with Shadow Dance.
Zeus
* Enchantress has a very low health pool, allowing Zeus to burst her down quickly before she can heal off the damage with Nature's Attendants.
* Zeus will not be affected by Untouchable, as he won't try to attack her with right clicks anyway.
* Zeus can stay out of her attack range while trying to kill her, especially if he has bought an 
Aether Lens.
* Most heroes would want to get on top of Zeus to kill him, but Enchantress does not have this option as doing so would severely limit her damage from Impetus.
* The exception is the laning phase, where Enchantress can gank Zeus if she Enchants a good creep.
Additional:
* Enchantress has a very low health pool, allowing Zeus to burst her down quickly before she can heal off the damage.
* Zeus will not be affected by 
Untouchable, as he won't try to attack her with right clicks anyway.
* Zeus can stay out of her attack range while trying to kill her, especially if he has bought an Aether Lens.
* Most heroes would want to get on top of Zeus to kill him, but Enchantress does not have this option as doing so would severely limit her 
Impetus damage.
* The exception is the laning phase, where Enchantress can gank Zeus if she Enchants a good creep.
Slark
* Heroes that can jump on her: Slark, Queen of Pain, Anti-Mage
Zeus
* Zeus can easily find Magnus who is often hiding in the trees with Thundergod's Wrath and Lightning Bolt, which allows him to warn allies and disrupt his initiation attempts.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Zeus
* Zeus's Lightning Bolt and Thundergod's Wrath provides a short duration of True Sight, revealing Riki while possibly dealing a heavy amount of damage.
* Zeus's Nimbus can be placed directly on top of 
Tricks of the Trade, potentially causing him to be damaged, stunned, and revealed the instant he becomes targetable again.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Zeus
* Since Windranger is bad against magical damage, heroes with continuous magical damage or magical nukes can blast her: Zeus, Tinker, Leshrac, Viper, Skywrath Mage, 
Lion, Lina, 
Venomancer.
Slark
* Pounce helps put Windranger in place, even when she uses 
Windrun to escape.
* Shadow Dance avoids Windranger's attacks from 
Focus Fire altogether, and he can regenerate his health and fight back after Windranger uses up all her abilities.
* The stun from 
Shackleshot and the slow from
Powershot can be both dispelled by Dark Pact, provided Slark casts it at the right moment.
Zeus
* Zeus can break Blink Dagger with his long range abilities and global range ultimate, Thundergod's Wrath.
* Lightning Bolt has a long range and a mini-stun, providing a way for him to cancel Black Hole from safe distances, assuming Enigma doesn't have his Black King Bar.
* Zeus's Aghanim's Scepter grants him Nimbus ability that has a global range and mini-stun, making it an even more effective way to cancel Black Hole before Enigma initiates with Black King Bar.
* Zeus is typically able to position himself at a safe distance from the fight, making him a difficult target to capture in a Black Hole.
Slark
* Enigma lacks burst damage, and that makes him vulnerable to heroes who can recover themselves and turn the fight around to their advantage after Enigma finishes his initiation: Faceless Void, Terrorblade, 
Ursa, Weaver, 
Broodmother, Slark, Abaddon, 
Wraith King, 
Lifestealer.
Zeus
* Heavy nukers will do well against Cold Embrace (Lina, Zeus etc).
Additional:
* Any ally that Winter Wyvern tries to save with 
Cold Embrace can still be damaged by all of Zeus's spells.
* If Winter Wyvern tries to juke vision by flying up a cliff or in the trees, Zeus can gain vision there with Lightning Bolt or Thundergod's Wrath.
* If Zeus is forced to attack an ally by 
Winter's Curse, his unimpressive attack damage and attack speed means they won't be hurt much by him. Zeus will also stay near the back of fights away from his allies, making a deadly Curse less likely.
Slark
* Arctic Burn and Splinter Blast's debuffs are can be dispelled with with Dark Pact. Arctic Burn also cannot be used to escape against Pounce.
* Even though Cold Embrace can protect it's owner from Slark's direct attacks, Slark can still gain Essence Shift stacks from attacking heroes affected by it.
* However, Essence Shift works against allies, and Slark's low health pool means that if he's the target for Winter's Curse, he will go down very quickly as Winter's Curse cannot be dispelled at all.
Zeus
* Lightning Bolt makes roaming behind enemy lines more and more difficult as Zeus becomes powerful enough to spam it. Also, Zeus' Ultimate Thundergod's Wrath reveals Bounty Hunter regardless of his position.
Additional:
* Bounty Hunter has a very low health pool, allowing Zeus to burst him down quickly.
* Zeus can cast Lightning Bolt to gain True Sight in any area he suspects Bounty Hunter may be invisible or any area he thinks Bounty Hunter may have warded.
* If Bounty Hunter tries to escape a gank by using 
Shadow Walk, Zeus can gain vision of him with both Lightning Bolt and Thundergod's Wrath.
Slark
* Slark with Dark Pact
* Heroes that can remove the Track debuff with their skills:
* Abaddon with 
Aphotic Shield and 
Borrowed Time
* 
Huskar with 
Life Break
* Juggernaut with Blade Fury
* 
Legion Commander with 
Press the Attack
* Lifestealer with 
Rage and 
Infest
* 
Naga Siren with 
Mirror Image
* 
Omniknight with 
Heavenly Grace
* 
Oracle with 
Fortune's End and 
False Promise
* Phantom Lancer with Doppelganger
* Slark with Dark Pact
* Ursa with 
Enrage
* Weaver with 
Time Lapse
* 
Tidehunter with 
Kraken Shell when damage received reaches the threshold.
Slark
* With Dust of Appearance, Luna will be able to use 
Eclipse on invisible heroes. Be mindful that Slark is exception because he'll be able to remove the debuff with Dark Pact.
Zeus
* Zeus's highly damaging nuke spells with low cooldowns is not something Luna can go against, though Luna can win against Zeus in late game.
* Thundergod's Wrath can be used before a fight to harm Luna before she activates Black King Bar, reducing her survivability for that fight.
* For the same reasons, Zeus makes a very powerful ally for Luna when they are in the same team.
Slark
* Shadow Dance prevents Luna from damaging Slark, and together with 
Silver Edge he can easily chase her or escape from her.
* Luna has no way to escape from Pounce's leash, which is especially bad as she is not used to buying 
Wind Waker, which is the only way to escape from Pounce outside of Black King Bar.
* For the same reasons, Slark makes a very powerful ally for Luna when they are in the same team.
Additional:
* Luna's lack of mobility and escape abilities makes her easily to gank for Slark.
* Shadow Dance helps avoid all the damage from Eclipse.
* For the same reasons, Slark makes a very powerful ally for Luna when they are in the same team.
Zeus
* Zeus is good against heroes that juke in trees or up cliffs, like Batrider, Monkey King, Spectre, and Tinker, by providing vision in any area with Lightning Bolt, or guaranteeing vision on enemies with Thundergod's Wrath.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Zeus
* Heroes who can provide True Sight or semi-reveal enemy heroes as Nature's Prophet is prone to buying Shadow Blade: Bounty Hunter, Slardar, Spectre, Zeus, Spirit Breaker.
Slark
* Pounce also stops 
Nature's Prophet's 
Teleportation.
Zeus
* Arc Lightning and Lightning Bolt can easily burst Terrorblade and his illusions.
* Static Field from Aghanim's Shard can automatically hit everything in a big radius, taking a huge chunk of health out of Terrorblade's illusions, regardless of how much health they have.
Slark
* Essence Shift allows Slark to hit Bristleback freely whether on the front or back, stealing attributes and make Bristleback much less tanky.
* Pounce can be used to disengage and recover lost HP with his ultimate passive, and can return to fight in a short period while Bristleback is already injured and got some of his attributes stolen.
* Dark Pact makes it near impossible to keep the 
Viscous Nasal Goo debuff on Slark.
* Although Dark Pact cannot dispel 
Quill Spray, meaning that Slark will still receive quill stack damage even if he used Shadow Dance before.
* Slark builds Silver Edge in almost every game, an item that greatly counters Bristleback.
Slark
* Sniper hugely lacks mobility and escape abilities so that he is an easy target for ganks from Slark.
Slark
* Dark Pact easily purges away both slow and disarm effect from Lucky Shot.
* With Pounce now applying leash to the target, Pangolier is helpless against Slark since both his Swashbuckle and Rolling Thunder will be disabled. Pounce also help Slark to easily escape from Rolling Thunder.
Zeus
* Arc Lightning has a low cooldown can used to pop his Linken's Sphere.
* Lightning Bolt or (Nimbus upgraded from Aghanim's Scepter) detects Weaver during Shukuchi, preventing his ganks.
* Thundergod's Wrath can kill Weaver quickly before he can cast his Time Lapse at low health.
Slark
* Pounce can easily break Static Link, making it less powerful against him.
* Slark is one of the few heroes who can man fight a Razor, because of Essence Shift.
* Shadow Dance can prevent Razor from killing him and may provide an opportunity to kill Razor due to it preventing Razor from attacking Slark.
Slark
* Heroes with AoE abilities will hit Slark in Shadow Dance: Lina, Jakiro, Underlord, Leshrac, Dark Seer, Earthshaker, Timbersaw, Crystal Maiden.
Additional:
* Timbersaw can use 
Chakram as a scouting tool to find Slark if he tries to Pounce into the trees.
* None of Timbersaw's abilities require a target to be cast, allowing him to hit Slark inside Shadow Dance.
* 
Reactive Armor can be effective protection against a Slark who attacks quickly, since the strong armor and health regen cannot be stolen by Essence Shift.
* 
Timber Chain makes Timbersaw very mobile, meaning he is among the very few heroes who can actually give chase to a fleeing Slark.
Zeus
* Zeus deals enormous amounts of magic damage, being one of the best heroes to burst down Timbersaw early in the game.
* Lightning Bolt's mini-stun can stop Timbersaw's from escaping a fight with Timber Chain.
Additional:
* Reactive Armor will not trigger from Zeus's spells or protect Timbersaw from their damage.
* Early game Timbersaw's strength is average and Zeus can heavily aid in bursting him down.
* Late game, if Timbersaw has built a lot of HP items, Zeus's passive Static Field will be more effective at chipping away Timbersaw's large HP pool.
* A Timbersaw who builds 
Pipe of Insight will be much more difficult to kill, as Zeus has no way to hold Timbersaw down, but Timbersaw will have less armor, mana, and damage than normal if he buys this item early game just to counter Zeus.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Slark
* Dark Pact dispels debuffs from Gush, Anchor Smash and even Ravage if timed correctly.
* Kraken Shell cannot restore attributes stolen by Essence Shift or dispel the leash if he gets Pounced.
Zeus
* Zeus greatly hinders Invoker on the line with his long-range abilities. QW- and QE-Invoker have a very long recharge on abilities, and Zeus' Arc Lightning ability recharges too quickly, which is why he quickly kills a pack of creeps and drives Invoker under his tower, punching and not letting finish off creeps
* Lightning Bolt and Thundergod's Wrath abilities reveal invisibility of enemies, for example Invoker invisibility from 
Ghost Walk ability
Additional:
* Zeus greatly hinders Invoker on the line with his long-range abilities. QW- and QE-Invoker have a very long recharge on abilities, and Zeus' Arc Lightning ability recharges too quickly, which is why he quickly kills a pack of creeps and drives Invoker under his tower, punching and not letting finish off creeps
* Lightning Bolt and Thundergod's Wrath abilities reveal invisibility of enemies, for example Invoker invisibility from Ghost Walk ability
Slark
* Earthshaker's many stuns can lock down slippery heroes like Slark in his Shadow Dance and Weaver in his 
Shukuchi.
Additional:
* Earthshaker's many AoE stuns help lock down Slark and will often waste the duration of Shadow Dance.
* As a frequent Force Staff buyer, he can later on escape or save teammates from Pounce.
Zeus
* Thundergod's Wrath will often disable Earthshaker's Blink Dagger before a fight starts.
Slark
* Heroes with invisibility and high mobility can jump on and focus down Earthshaker before he has a chance to initiate: Clinkz, Slark, Storm Spirit
Slark
* Slark's Pounce allows him to close the gap on Phantom Assassin and prevent her from escaping with 
Phantom Strike.
* As a hero who typically builds Silver Edge, Slark can use it to disable Phantom Assassin's 
Blur and 
Coup de Grace, thus taking down her attack evasion and drastically reducing her damage output.
* Because Phantom Assassin is always reliant on critical strikes, Slark will have plenty of time to escape with Pounce, Shadow Dance and Silver Edge (provided that he purchased it already).
* Depth Shroud from Aghanim's Shard will allow Slark to save both, himself and his allies from Phantom Assassin with Shadow Dance, and to freely fightback against her without removing invisibility upon attacking.
* Essence Shift is much more harmful for Phantom Assassin than for other heroes, as losing the agility means that her physical damage will be also reduced, which can also weaken Coup de Grace if Slark manages to steal lots of agility from her.
* Overall, any attempt for Phantom Assassin to take down Slark will hurt her more than Slark.
Additional:
* Slark's Pounce allows him to close the gap on Phantom Assassin and prevent her from escaping with Phantom Strike.
* As a hero who typically builds Silver Edge, Slark can use it to disable Phantom Assassin's Blur and Coup de Grace, thus taking down her attack evasion and drastically reducing her damage output.
* Because Phantom Assassin is always reliant on critical strikes, Slark will have plenty of time to escape with Pounce, Shadow Dance and Silver Edge (provided that he purchased it already).
* Depth Shroud from Aghanim's Shard will allow Slark to save both, himself and his allies from Phantom Assassin with Shadow Dance, and to freely fightback against her without removing invisibility upon attacking.
* Essence Shift is much more harmful for Phantom Assassin than for other heroes, as losing the agility means that her physical damage will be also reduced, which can also weaken Coup de Grace if Slark manages to steal lots of agility from her.
* Overall, any attempt for Phantom Assassin to take down Slark will hurt her more than Slark.
Zeus
* Necrophos' 
Ghost Shroud increases the magic damage taken by Necrophos.
* If Zeus builds both an 
Ethereal Blade and Veil of Discord, it almost always guarantees a kill.
Slark
* Dark Pact can dispel Venomous Gale and Poison Sting.
* Shadow Dance allows Slark heightened regeneration when out of vision making DoTs effects less threatening.
Zeus
* Zeus can reveal Clinkz with Lightning Bolt.
* He is vulnerable to Zeus's magical nukes, due to his low health pool.
Slark
* Shadow Dance allows Slark to not be targeted by Unstable Concoction, making Alchemist stun himself and making himself vulnerable to the enemy.
* Dark Pact also allows him to just purge off the stun if timed correctly.
* Essence Shift will steal stats over long durations at a time should Alchemist lack the damage to kill Slark.
Slark
* Pounce's root prevents Earth Spirit from using Rolling Boulder to escape, making it easier for Slark to shut him down especially in the laning phase.
Slark
* Dark Pact, if timed correctly, can dispel Wraithfire Blast's stun and slow.
* Since Wraith King has a lot of health and multiple lives, Slark can keep gaining Essence Shift stacks, increasing armor, damage, and attack speed and can beat down Wraith King twice.
* Slark sometimes carries 
Diffusal Blade to burn mana as an attempt to shut down Reincarnation.
* Because Wraith King has no AoE abilities, Shadow Dance is particularly useful against Wraith King.
Slark
* Dark Pact dispels Ignite's slow and Fireblast's stun.
* Shadow Dance allows Slark to regenerate HP, even when he is affected by Ignite and Fireblast.
Slark
* 
Upheaval does not interrupt Slark too much, as he can just Pounce out of the area.
* 
Fatal Bonds and 
Shadow Word can be dispelled by Dark Pact.
Zeus
* Lich does not pose a big threat to Zeus in teamfights, as his spells don't have great cast range and Zeus should be too far back for a 
Chain Frost to bounce among him and his allies.
* Lich has a low health pool, allowing Zeus to burst him down quickly.
Slark
* Heroes that can easily bypass Chen's creeps to get to Chen: Riki, Tusk, Clinkz, Sniper, Slark, Phantom Assassin, 
Void Spirit, Storm Spirit, Ember Spirit, Earth Spirit, Spirit Breaker.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Zeus
* Although Lightning Bolt and Thundergod's Wrath can reveal Templar Assassin during Meld, Zeus nonetheless has no way to deal with Refraction.
* Zeus is a rather squishy hero, falling easily to Templar Assassin's high burst damage.
Additional:
* 
Refraction blocks all of Zeus' damage and Zeus has no innate way of removing the instances quickly.
* 
Meld helps burst down Zeus' small health pool while he's still working through the Refraction instances.
* 
Psi Blades allow her to harass and zone Zeus in lane.
* Templar Assassin usually buys Blink Dagger, enabling her to quickly close the gap to Zeus' defensive positioning.
Zeus
* Heroes who can provide True Sight are always credible threats: Slardar, Bounty Hunter, especially Zeus since his Lightning Bolt provides True Sight without the need to detect her beforehand to apply the debuff. So even a late-coming Zeus can easily scout a large area to reveal her, and she cannot purge herself from his sight with the dispel talent.
Slark
* Dark Pact rips through Refraction charges and still steals attributes during Refraction.
* Pounce and Dark Pact will still hit Templar Assassin while she is Melded. Since she cannot move, both abilities will be easy for Slark to land.
Slark
* Heroes with strong dispels can remove Primal Roar's stun: Abaddon, Slark, Oracle.
Zeus
* Heroes with high magical burst damage will kill Gyrocopter before he gets to do much: Lina, Lion, Zeus
Zeus
* Heroes with mediocre health pools who rely on armor or evasion to survive fights such as Troll Warlord, 
Windranger, and Terrorblade can be killed by Zeus if caught off guard.
Zeus
* Zeus burst damage can be reduced by 
Dispersion and reflect some of the damage back to Zeus himself.
* Zeus has low mobility and stays in backlines, 
Spectral Dagger or 
Haunt can easily catch him as he has no escape mechanism.
* Since Zeus has low HP, Spectral Dagger and 
Desolate will quickly tear Zeus down when he's alone.
Zeus
* Zeus is good against heroes that juke in trees or up cliffs, like Batrider, Monkey King, Spectre, and Tinker, by providing vision in any area with Lightning Bolt, or guaranteeing vision on enemies with Thundergod's Wrath.
Slark
* Essence Shift deals 20 extra damage by draining one strength per hit, which cannot be reduced or spread by Dispersion.
* Pounce prevents Spectre from escaping with Spectral Dagger.
* Haunt illusions usually don't deal a lot of damage to Slark as he tends to buy a Shadow Blade, preventing Desolate's and Diffusal Blade's damage and activating Shadow Dance's regeneration to make up for any damage caused by 
Radiance.
* Slark is a natural carrier of Silver Edge, which helps break both Desolate and Dispersion.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Slark
* Heroes that can easily bypass Io's allies to get to Io: Riki, Tusk, Clinkz, Sniper, Slark, Phantom Assassin, Void Spirit, Storm Spirit, Ember Spirit, Earth Spirit, Spirit Breaker, Lifestealer.
Slark
* Heroes who build Black King Bar as either core or situational item will be able to fight back against Nyx Assassin and freely attack him as Spiked Carapace cannot pierce spell immunity at all: 
Axe, Broodmother, 
Dawnbreaker, Enigma, Huskar, Jakiro, Legion Commander, Lina, 
Luna, Lycan, Slardar, Slark, Troll Warlord, Witch Doctor.
Slark
* Heroes who have a high mobility (Queen of Pain, Storm Spirit, Slark, etc.).
Slark
* Nyx Assassin, Bounty Hunter and Slark can all sneak up and kill Shadow Shaman, Nyx being particularly deadly. Shadow Shaman must watch out for Slark carefully, as he can break either (but not both unless he makes a mistake) of Shadow Shaman's disables, with Dark Pact and leap out of a serpent ward ring. These heroes, however, rely heavily on escape and are themselves not very durable and none of them can survive a full lockdown with Mass Serpent Ward. Having Sentry Wards can turn Shadow Shaman from prey to predator.
Slark
* Slark will have a hard time killing Sand King because of the survivability he gets from Burrowstrike and Sand Storm.
* Shadow Dance, which usually allows Slark to survive fights, is ineffective against Sand King's AoE damage.
Zeus
* Zeus usually stays at the back in teamfights and it is hard for Sand King to find Zeus and knock him down before Zeus deals his damage.
* All of Zeus' abilities, especially Thundergod's Wrath, disables Sand King's Blink Dagger, effectively reducing Sand King's initiation and counter-initiation potential.
* Lightning Bolt deals damage to Sand King in Sand Storm and reveals him. It also interrupts channeling of Epicenter.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Slark
* Melee carries who usually buy an early Black King Bar, and have gap closing abilities can be good against the Arc Warden, such as Slark, Riki, Earthshaker with Aghanim's Scepter, Sven with Aghanim's Scepter etc.
Additional:
* 
Flux is dispelled by Dark Pact.
* Pounce allows Slark to avoid 
Spark Wraiths.
* 
Tempest Double allows Slark to build up Essence Shift stacks, especially when it is being used for split pushing.
Zeus
* Heroes with global abilities can give Legion Commander's opponent an edge in Duels from anywhere on the map: Nature's Prophet, 
Ancient Apparition, Zeus, Invoker, Treant Protector
Slark
* Rubick usually positions in the back of a team. Heroes who can sneak up and assault Rubick (e.g. Slark) or damage Rubick from great distance (e.g. Spectre, Sniper) should be treated cautiously, as otherwise the matchup usually ends up badly for Rubick.
Slark
* Pounce and Dark Pact together with some attacks can take Rubick down quickly.
* Rubick's spells are ineffective due to the strong dispel effect of Dark Pact.
* Even though Shadow Dance is a great spell to steal, Slark's untargetable nature and his low cooldown spells prevents Rubick from stealing. Also Slark can freely use other abilities for the duration of Shadow Dance.
Slark
* Heroes with heavy magical nukes will take advantage of Slark's poor HP or force him to use Shadow Dance early: Lina, Lion, Zeus
Slark
* Dark Pact can be cast during the cast animation of Light Strike Array and dispel its stun.
* Pounce allows Slark to close the gap to Lina.
* Shadow Dance prevents Lina from killing Slark with her Laguna Blade when his HP gets low.
Slark
* 
Ensnare prevents using any kind of movement abiilties, Making Naga Siren good against heroes who rely on gap-closing abilities to escape: Phantom Assassin, Magnus, Slark, Riki, Faceless Void, Storm Spirit.
Zeus
* Zeus's abilities deal high amounts of burst magical damage, which ignores Naga Siren's high armor.
* Arc Lightning is a good way to destroy Naga Siren's illusions due to it's capabilities to bounce between enemies.
* Static Field from Aghanim's Shard can automatically hit everything in a big radius, taking a huge chunk of health out of Naga Siren's illusions, regardless of how much health they have.
Slark
* Slardar's level 25 talent makes 
Corrosive Haze undispellable, thus providing his allies vision of Slark.
Zeus
* Slardar has high priority on building moblity items such as Blink Dagger rather than tank items. Zeus can easily deal large amount of damage to him if not caught out of position first.
Slark
* Heroes with heavy magical nukes will take advantage of Slark's poor HP or force him to use Shadow Dance early: Lina, Lion, Zeus
Slark
* Lion's lack of escapes gives Slark easier time to catch him through Pounce.
* Shadow Dance gives Slark the advantage of being untargetable, nullifying single target abilities (such as non-upgraded 
Hex, 
Mana Drain and 
Finger of Death).
* Dark Pact applies multiple instances of strong dispel on Slark, which is strong against any of Lion's disables.
* Lion's low health pool and low armor make him extremely vulnerable to Slark's damage output.
Zeus
* As a spellcaster, silences will nullify him entirely. Some notable examples are Death Prophet, Drow Ranger, Bloodseeker, Disruptor and many others.
* Doom, as usual, fits this description nicely.
Slark
* A well-timed Dark Pact can dispel Frost Arrows and Gust, letting Slark engage and escape freely.
* Essence Shift is very detrimental for Drow Ranger as the loss of agility means that Marksmanship will also suffer from getting weakened.
* Shadow Dance lets Slark quickly close the gap and deal heavy damage without giving Drow Ranger a chance to retaliate.
* Pounce counteracts Frost Arrows's slow, and also allows Slark easily pin Drow Ranger down or flee from her.
* Depth Shroud from Aghanim's Shard will allow Slark to save both, himself and his allies and will also allow them to freely fight back against Drow Ranger without her noticing them.
Additional:
* Pounce and items like Shadow Blade makes it very difficult for Drow Ranger to keep her distance from Slark, thereby losing her 
Marksmanship bonus.
* 
Gust is rarely enough to keep Slark at bay, as Drow Ranger has no movement abilities and will simply be chased down afterwards.
* Drow Ranger's heavy dependence on agility also makes her significantly weaker after being drained by Essence Shift.
Zeus
* Heroes who have most or all their abilities (damage or disable) unable to pierce spell immunity: 
Keeper of the Light, Lina, Lion, Zeus.
Additional:
* Rage is very useful against Zeus, as it negates magic damage and provides spell immunity. In addition, the increased attack speed can tear Zeus apart in combination with 
Open Wounds.
* Lifestealer can avoid Thundergod's Wrath with Infest.
Slark
* Shadow Dance allows Slark to attack Lifestealer for its duration without any way for Lifestealer to fight back, allowing him to steal his stats with Essence Shift, which also reduces Lifestealer's strength and, therefore, health pool.
* Slark can easily escape Lifestealer with Pounce, and can avoid Open Wounds with Dark Pact should Lifestealer be forced to itemize for it.
* Slark commonly buys a Silver Edge, which can break Lifestealer's Feast, severely diminishing his damage output and lifesteal.
* Depth Shroud from Aghanim's Shard allows Slark to save both, himself and his allies with Shadow Dance while also allowing them to fight back against Lifestealer.
Zeus
* Heroes with a lot of burst damage, especially those who rely on casting spells: Lina, Zeus.
Slark
* Medusa is especially vulnerable to Essence Shift, as both strength and intelligence contribute to her effective HP, while agility contributes to her damage.
* Dark Pact when timed right can be used to dispel Stone Gaze right after it petrifies Slark, allowing him to keep attacking Medusa throughout the duration.
Additional:
* Medusa cannot chase Slark in any way and has no disable beyond her ultimate, making her unable to stop him getting away and regenerating before coming back to finish her off.
* Essence Shift particularly removes 1 intelligence point per hit, thus lowering Medusa's mana pool's cap and leaving her much more vulnerable in prolonged fights.
Slark
* Slark's low health and reliance on high built armor from Essence Shift makes him susceptible to Muerta's 
Pierce the Veil.
* Muerta cannot be attacked by Slark's physical attacks and Essence Shift during Pierce the Veil.
* Muerta's 
Dead Shot and 
The Calling can hit Slark even while hidden with Shadow Dance.
Zeus
* Zeus's enormous magical damage output makes Pierce the Veil risky to use without a Black King Bar.
* Zeus does not rely on attack speed, making The Calling nearly pointless against him.
* If Zeus is ever too close to Muerta, he can use 
Heavenly Jump to disengage.
Zeus
* Heroes with long range abilities are also able to touch Zeus, such as Clockwerk, Kunkka, Puck, Skywrath Mage, Spirit Breaker, Tusk and others.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Slark
* Bulwark blocks much of Slark's basic attack damage, even during Shadow Dance.
* Slark finds it very difficult to have a good early/mid game when pressured in the early game by Spear of Mars and God's Rebuke.
* Spear of Mars and God's Rebuke can hit Slark through Shadow Dance and Depth Shroud.
* Should Pounce be on cooldown, Slark is very vulnerable inside Arena of Blood.
Zeus
* Mars' own father is a formidable foe because Zeus deals massive amounts of magical damage. The high damage, low cooldown nukes of Arc Lightning and Lightning Bolt combined with the percent health magic damage of Static Field will shred Mars' health because it bypasses Bulwark completely.
Slark
* Heroes that can deny Slark early kills will prevent him from snowballing: Dazzle, Abaddon.
Zeus
* Some heroes with extreme range, like Zeus, Invoker or Clockwerk, can snipe your allies from anywhere after your Grave has expired.
Zeus
* Zeus likes to stay far back in fights, dealing his damage uninterrupted, but once he gets hooked into the fight, he usually dies very quickly.
* Pudge's high strength from Flesh Heap makes it very hard for Zeus to burst him down.
* Zeus' low health pool makes him very vulnerable to the damage from Meat Hook, Rot and Dismember.
Additional:
* 
Meat Hook's high range allows Pudge's team to drag Zeus in the middle of the fight and abuse his frailty.
* 
Flesh Heap's health and magic resistance bonus makes Pudge exceptionally resistant to Zeus' nukes. In later stages of the game, Zeus is usually unable to seriously damage Pudge at all. Even Static Field, which deals damage based on a percentage of the enemy's health, won't be doing much.
* Even if Zeus buys a Black King Bar, Meat Hook and 
Dismember still disable him for a long time, usually causing Zeus' quick death.
* Zeus is vulnerable to early ganks, which Pudge excels at.
Slark
* Dark Pact dispels Dismember if timed correctly.
* Pounce allows Slark to escape Pudge's Rot once Dismember is over, and allows him to dodge hooks.
* Shadow Dance hides Slark and grants him a high degree of mobility, which can make him a difficult target to hook and also protects him from Pudge's Dismember (including allies with an Aghanim's Shard).
Zeus
* Heroes with long range abilities are also able to touch Zeus, such as Clockwerk, Kunkka, Puck, Skywrath Mage, Spirit Breaker, Tusk and others.
Slark
* Heroes with blink or movement abilities, which are disabled by Pounce's leash: Anti-Mage, Earth Spirit, Faceless Void, Magnus, Mirana, Monkey King, Morphling, Pangolier, Phantom Assassin, Phoenix, Puck, Queen of Pain, Riki, Sand King, Spirit Breaker, Timbersaw, Tusk.
Slark
* Melee carries during the laning phase: Sven, Slark
Slark
* Heroes with dispels: Legion Commander, Oracle, Slark, Phantom Lancer
Slark
* Heroes with AoE abilities will hit Slark in Shadow Dance: Lina, Jakiro, Underlord, Leshrac, Dark Seer, Earthshaker, Timbersaw, Crystal Maiden.
Slark
* 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.
Slark
* Shadow Dance does not protect Slark from Shadow Fiend's AoE spells.
Zeus
* Arc Lightning allows Zeus to get farm in lane against Shadow Fiend without coming into the range of his Shadowrazes.
* Lightning Bolt can be used to heavily harass Shadow Fiend when he tries to get a last hit.
* Thundergod's Wrath and Lightning Bolt can be used to detect Shadow Fiend if he tries to escape with Shadow Blade.
Zeus
* Once you get a Black King Bar, squishy spellcasters like Zeus, Skywrath Mage and others will be probably easy to deal with.
Slark
* Lycan cannot escape from a Pounce even if he uses 
Shapeshift, and has no disabling abilities to stop Slark.
Zeus
* Enrage will make it very difficult to burst him down.
* Zeus has little armor, HP and mobility; Ursa's favorite kind of target.
Slark
* Slark can detect early Roshan attempts due to Shadow Dance if he frequently checks the Pit.
* Enrage cannot restore attributes stolen by Essence Shift and will reduce his physical damage output.
* Even if Ursa initiates with Earthshock, Slark can Pounce away or use Dark Pact after Ursa's initiation to avoid Fury Swipes' damage until Earthshock's slow is gone.
Zeus
* Heroes with long range abilities are also able to touch Zeus, such as Clockwerk, Kunkka, Puck, Skywrath Mage, Spirit Breaker, Tusk and others.
Slark
* Clockwerk lacks burst damage, and that makes him vulnerable to heroes who can recover themselves and turn the fight around to their advantage after Clockwerk finishes his initiation. Additionally, Clockwerk hates buying 
Dagon and Ethereal Blade, which are the only itmes that can help him deal with heroes who can recover themselves and turn the fight around to their advantage: Faceless Void, Terrorblade, Ursa, Weaver, Broodmother, Slark, Abaddon, Wraith King, Lifestealer.
Slark
* Heroes with AoE abilities will hit Slark in Shadow Dance: Lina, Jakiro, Underlord, Leshrac, Dark Seer, Earthshaker, Timbersaw, Crystal Maiden.
Zeus
* 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.
Zeus
* Even though Pugna's low HP means that he can be quickly burst down, his
Nether Ward heavily punishes casters whose spells cost a lot of mana, like Zeus. Casting 4 of his active spells, including Nimbus, close to an enhanced level 4 
Nether Ward, can make the ward deal up to 1750 magical damage.
Decrepify can further increase the damage dealt by Nether Ward upon Zeus. However, if used on Pugna himself or on one of his allies, it will amplify the damage done by Zeus' abilities.
*
Slark
*
Nether Blast will still hit Slark even if he is hidden during Shadow Dance.
Decrepify, he can still use it defensively on an ally to prevent Slark from getting stacks.
Life Drain.
* Even though Pugna can rarely target Slark directly with
* Despite being somewhat easy to break with Pounce, Pugna can damage Slark and provide vision over him with