* 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.

* Heroes with hastes: Dark Seer, Lycan

* Voodoo Restoration heals to counter damage over time of Poison Nova and Poison Sting.

* Heroes with channeling abilities: Enigma, Witch Doctor, Crystal Maiden.

* Venomancer's damage-over-time abilities do little damage against Counterspell.
* Blink helps Anti-Mage get away from Venomancer's slows.
Additional:
* Counterspell provides magic resistance, diminishing the effectiveness of Venomancer's spells.
* Venomancer's lack of hard disable allows Anti-Mage to use Blink, circumventing the slows Venomancer depends on.

* Being an intelligence caster hero, Ezalor usually has a high mana pool and low health and armor, making him a prime target for Mana Void
* Ezalor's Illuminate damage and Solar Bind's magic resistance reduction are greatly reduced thanks to Counterspell. Counterspell can also block and reflect Solar Bind if timed properly.
* Anti-Mage usually is not hampered by Solar Bind or Will-O-Wisp thanks to Blink.
* However, despite all of this, if Keeper of the Light is played carefully and tops off his team's mana at all times, Anti Mage will not be able to get off a good Mana Void.
* By the same token once Keeper of the Light gets a Octarine Core, he can spam Charka Magic to keep his own mana full

* Vulnerable spellcasters with no escape mechanisms are easy targets for Huskar: Lich, Crystal Maiden, Silencer, Keeper of the Light, Venomancer, etc.

Additional:
* Huskar can easily regenerate lost health from DoT spells through Berserker's Blood rendering them ineffective
* Venomancer has little armor and mobility, and rarely builds Linken's Sphere, so he is quite vulnerable to Life Break.

* Vulnerable spellcasters with no escape mechanisms are easy targets for Huskar: Lich, Crystal Maiden, Silencer, Keeper of the Light, Venomancer, etc.

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

* With Bloodthorn, Clinkz becomes a strong counter to heroes who rely on evasion and blind such as Windranger, Phantom Assassin, Troll Warlord and Keeper of the Light.

* Fortune's End and False Promise easily dispel many crippling debuffs, such as Venomancer's Venomous Gale, or Skywrath Mage's Ancient Seal.

Additional:
* Fortune's End can dispel Venomous Gale and Poison Sting from allies.
* Fate's Edict grants 100% magic resistance to target, inhibiting the damage from Venomancer abilities.

* Heroes with dispels: Legion Commander, Oracle, Slark, Phantom Lancer

* Squishy heroes or heroes without hard disables or silences: Shadow Demon, Shadow Fiend, Venomancer, Ancient Apparition etc.

* Heroes with teleports to escape Solar Blind and Will-O-Wisp: Phantom Assassin, Puck, Queen of Pain, Storm Spirit

* Being a cast-oriented hero, Ezalor will suffer from all of Silencer's abilities.
* Global Silence is a guaranteed lengthy silence which will render Ezalor useless in a teamfight.
* Arcane Curse and Last Word are good against any caster, since they are extremely potent.
* However, it should be worth mentioning that a smart Ezalor will buy Eul's Scepter of Divinity to dispel Silencer's abilities. Combined with the level 20 talent (Chakra Magic applies a basic dispel), Ezalor can purge Silencer's abilities off allies and himself alike.

* Venomancer's damage-over-time abilities are easier to heal through with numerous Shadow Waves than other types of damage, and it's simple to time a Shallow Grave until the last possible second to save a teammate from them.

* Crippling Fear prevents Keeper of the Light from using his spells to keep his team alive during team-fights.
* Dark Ascension is very strong against Keeper of the Light, as it allows Night Stalker to jump the backline and quickly kill the squishy Ezalor, especially when combined with the slow from Void.
Additional:
* Keeper of the Light's Aghanim's Scepter upgrade loses much of its power, due to Night Stalker being able to reduce the duration of daytime by a lot.

* Heroes rely on their debuff to control the opponent will have a hard time against Press the Attack: Venomancer, Earth Spirit, Ogre Magi

Additional:
* Press the Attack dispels Venomous Gale and Poison Sting from Legion Commander or her teammates.
* Venomancer is an ideal target for Duel due to his lack of mobility and low starting health.

* Press the Attack can dispel Blinding Light or Solar Bind from a hero.
* Duel can be used to instantly take Keeper of the Light out of a team-fight.

* Dark Pact can dispel Venomous Gale and Poison Sting.
* Shadow Dance allows Slark heightened regeneration when out of vision making DoTs effects less threatening.

* Heroes with dispels: Legion Commander, Oracle, Slark, Phantom Lancer

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

* Venomancer has low health, which makes him vulnerable to Lina's heavy magic damage.
* Fiery Soul attack speed bonus removes Plague Wards easily in all stages of the game.

* Snowball can be used to save allies or himself during Venomous Gale and Poison Nova.
* Venomancer lacks mobility and has low base health, so he can be killed by Walrus PUNCH!

* Blood Rite makes Ezalor chose between getting off Illuminate or getting silenced for a while, as Illuminate is a channeled ability.
* Blood Rite's silence can completely take Ezalor out of a teamfight, as he relies on his abilities to be useful.
* Keeper of the Light's only mobility source, his high movement speed (via his high base movement speed and through spirit form), is entirely countered by Rupture.

* Rage allows him to be immune to all of Ezalor's abilities. Also, the increased movement speed combined with the slow from Ghoul Frenzy and the squishy nature of Ezalor allows Lifestealer to take him down very quickly.

* In the laning stage, making illusions of Venomancer will turn his Poison Sting back at him, making for an easy gank at level one, and for later when your mid comes for ganks.

* Venomous Gale is a great ganking and farming skill.
* Plague Ward serves as a flexible ability for pushing, ganking, farming and scouting. The innate Poison Sting also works on the stolen Plague Ward with half the damage.
* Poison Nova, if stolen and cast, puts a huge damage-over-time debuff on the enemy team, even greater than Venomancer himself with the help of Arcane Supremacy.
* Spell Steal has a greater cast distance than the effect area of Poison Nova, allowing Rubick to steal the spell while staying at the back.
* Venomancer suffers from mana pool problems, while Rubick has relatively high intelligence gain and can cast the same set of spells at ease.
Additional:
* All of Venomancer's abilities are decent choices for Rubick's Spell Steal. Stealing Plague Wards makes them apply Poison Sting as well.

* Sniper can easily destroy Plague Ward from long range.

* Heroes with silences: Puck, Doom, Riki.

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

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

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

* Jakiro's reliance on his abilities can cause struggles for heroes who rely on evasion or blinds to get upper hand: Phantom Assassin, Windranger, Riki, Troll Warlord, Keeper of the Light.

* Heroes that deal damage over time will also fail to bring down Abaddon and his allies, such as Huskar, Venomancer, or Phoenix.

Additional:
* Borrowed Time & Aphotic Shield can dispel Venomous Gale and Poison Sting.

* Slardar can attack through Plague Wards and gain Bash of the Deep charges, and Templar Assassin can spill Psi Blades through Plague Wards too.

* Heroes with dispels: Legion Commander, Oracle, Slark, Phantom Lancer

* Any hero who lanes very poorly will struggle with Primal Beast's potential snowball in the very early levels, like Keeper of the Light, Luna, Templar Assassin...

* Heroes with channeling abilities: Enigma, Witch Doctor, Crystal Maiden.

* Squishy heroes, usually supports, like Lion, Ancient Apparition, Keeper of the Light etc can die quickly to Tiny's magic burst.

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

* Heroes with silences: Puck, Doom, Riki.

* Heroes who lack escape mechanisms or disables are all easy targets for Phantom Assassin if they are not careful. Look for Luna, Venomancer, and Shadow Fiend and try to catch them off guard.

* Heroes with teleports to escape Solar Blind and Will-O-Wisp: Phantom Assassin, Puck, Queen of Pain, Storm Spirit

* Heroes with teleports to escape Solar Blind and Will-O-Wisp: Phantom Assassin, Puck, Queen of Pain, Storm Spirit

* Mana Drain is very effective against heroes that have mana burn abilities such as Anti-Mage, Nyx Assassin and Keeper of the Light.

* Heroes with damage-over-time abilities will not only proc Bristleback's passive continuously, they will also do little harm to him when he is facing away from the source: Venomancer, Arc Warden

* Spiked Carapace can be used to reflect Illuminate damage and stun Keeper of the Light.
* Vendetta allows Nyx Assassin to follow Keeper of the Light around if he tries to split-push.
* Keeper of the Light is very squishy and will very quickly die to Vendetta and it's followup abilities.
* However, Mana Burn's Mana Burn can be more or less mitigated with Chakra Magic.

* Juggernaut's Healing Ward keeps his team healthy even when pushing against Keeper of the Light's Illuminate.
* Blade Fury can dispel Blinding Light, as well as dodge an incoming Illuminate. Juggernaut can attack towers during Blade Fury, so he can dodge an Illuminate without having to stop pushing.
* Should Keeper of the Light obtain Will-o-Wisp through purchasing an Aghanim's Scepter, Juggernaut can make quick work of Ignis Fatuus without being interrupted by its pull.
* Keeper of the Light has low health, low armor, and no natural defense against Blade Fury.
Additional:
* Blade Fury allows him to be immune to all of Ezalor's abilities.
* Healing Ward heals his entire team, mitigating Ezalor's weak magical burst damage.

* Corrosive Skin means Viper can often outlast Venomancer in a battle of attrition.
* Venomancer has no mobility without items, which makes him vulnerable to constant slows.

* While Reincarnation is off cooldown, Poison Nova poses less of a threat as Wraith King will return with all debuffs cleared.
* Vampiric Spirit can out-heal the slow {tooltip:DoT|Damage over Time} from Poison Sting.

* Teleportation allows Natures Prophet to save himself from the damage over time of Venomous Gale, Poison Sting and Poison Nova.
* Plague Wards can be destroyed with Nature's Prophet's Treants.

* Slardar can attack through Plague Wards and gain Bash of the Deep charges, and Templar Assassin can spill Psi Blades through Plague Wards too.

* Heroes that can jump and kill him: Meepo, Clinkz, Templar Assassin