* Impetus is not blocked by Guardian Angel. A {U:Satyr Banisher} can also be controlled to dispel Guardian Angel.
Additional:
* Enchantress's Impetus deals pure damage instead of physical damage and ignores Guardian Angel, thus fully negating one of Omniknight's most important abilities for teamfights.
* Similar to Doom, Enchantress can use Enchant on Satyr Banisher, which will give her access to Satyr Banisher's Purge, and allow her to remove Heavenly Grace and Guardian Angel.

* Untouchable greatly reduces Chemical Rage's attack speed advantage.

* Heroes with large magical AoE damage will fare well against Omniknight: Lich, Ancient Apparition, Jakiro, Disruptor.

* Ice Blast cancels out Chemical Rage's rapid health regeneration. It can also take advantage of Alchemist's Armlet of Mordiggian toggling, as it will make HP drain insanely fast, essentially killing the bearer in no time.
Additional:
* Ice Blast nullifies the health regeneration granted by Chemical Rage, which Alchemist greatly relies on to stay alive in battle.
* Alchemist tends to build Armlet of Mordiggian which can be deadly during Ice Blast.

* Heroes that can purge buffs can dispel Guardian Angel: Invoker, Shadow Demon, Oracle.

Additional:
* Demonic Purge can dispel Guardian Angel on the key target during combat, allow your allies to finish them.

* Alchemist is a well-known Radiance carrier among other auras your illusions will benefit from. They also get the extra move speed and reduced base attack time from his Chemical Rage, and it's even better if you can catch him as his own rage is about to expire.
* Disruption will buy enough time for all allies to retreat when Alchemist starts to activate Unstable Concoction.

* Heroes with naturally low mana can be easily shut down by E.M.P.: Sven, Tiny, Wraith King, Omniknight

Additional:
* Tornado dispels Heavenly Grace and Guardian Angel from multiple targets.
* Guardian Angel is generally useless against Invoker as he primarily relies on magical damage.
* E.M.P. depletes Omniknight's already small mana pool.
* Invoker's many disables keep Omniknight's team occupied until Guardian Angel times out.

* Quas-Exort Invoker can win the mid lane easily against Alchemist because Quas regeneration will nullify Acid Spray's damage over time and Exort damage bonus will allow Invoker to out last hit Alchemist.

* Guardian Angel does not offer protection from Eclipse, though it will negate damage from Moon Glaives.
* Luna's high magical damage from Lucent Beam and Eclipse can often finish allied heroes before Omniknight can save them with Purification.
* Likewise, Luna's high physical damage from Moon Glaives and Lunar Blessing is strong enough to counter debuff immunity from Repel.
Additional:
* Guardian Angel does not offer protection from Eclipse, though it will negate damage from Moon Glaives.
* Luna's high magical damage from Lucent Beam and Eclipse can often finish allied heroes before Omniknight can save them with Purification.

* Heroes who are melee but cannot fight back against Eclipse will really struggle with Luna: Monkey King, Alchemist, Timbersaw.

* Jingu Mastery will still add stacks even through Guardian Angel.
* Monkey King can join a fight whenever he chooses to, meaning he can simply go directly onto Omniknight.
* During the laning phase, Jingu Mastery with Boundless Strike will kill off Omniknight, while Purification is weak.
* Heavenly Grace is useless against Monkey King's ultimate and Jingu Mastery bonuses.

* Alchemist has very bad armor and does not build armor items for the large majority of his build, so Jingu Mastery and Wukong's Command can be very deadly.
* Desolator, Sange and Yasha or Diffusal Blade can all be purchased to increase your damage against Alchemist or just to keep your movement speed high enough to match him while Chemical Rage is active.
* Monkey King is an agility hero and scales with armor, so Acid Spray loses it's effectiveness later in the game.

* Heroes who can harass Omniknight out of lane will keep him weak in the mid game: Viper, Venomancer, Clinkz.

* Viper can bully Alchemist out of mid lane quite easily, forcing him to either retreat into jungle, or stay harassed in lane, and get very few last hits. Vipers break also completely disables Greevil's greed which prevents Alchemist to earn his amazing amounts of money.

* Heroes who can harass Omniknight out of lane will keep him weak in the mid game: Viper, Venomancer, Clinkz.

* Clinkz can use Burning Army in teamfights which will cause a problem for Alchemist.

* Heroes with large physical resistance do not counter Muerta's Pierce the Veil such as Omniknight or Tidehunter.

* Heroes who rely on physical damage output to be effective will fare badly against Muerta's Pierce the Veil: Phantom Assassin, Terrorblade, Drow Ranger, Lifestealer, Anti-Mage, Alchemist, Lycan, Clinkz, Sniper.

* Feast is good against high health strength heroes such as Alchemist.
* Rage allows Lifestealer to not be targetable by Unstable Concoction, possibly making Alchemist stun himself.
* Since Lifestealer build Aghanim's Scepter upgrades Infest similliar Heaven's Halberd can applies an undispellable disarm so Alchemist cannot attack during Chemical Rage, forcing him to activate Black King Bar beforehand.

* Fortune's End's AoE dispel will remove Heavenly Grace and Guardian Angel.
Additional:
* Oracle can dispel Heavenly Grace (which he can also bait out with Fate's Edict).
* With Fortune's End, Oracle can dispel Guardian Angel in an area of effect.

* Alchemist likes to farm fast and be ahead, unfortunately Lone Druid likes to do the same by taking towers.
* Acid Spray will never prove a threat to Lone Druid or his Spirit Bear.
* Chemical Rage may not prove so useful once Lone Druid procs entangled keeping him in place.
* Monkey King Bar is a very good choice on Lone Druid's Spirit Bear and it directly counters any potential Radiance from Alchemist.
* Assault Cuirass is another very good Spirit Bear item that further makes Alchemist vulnerable to physical damage, which is all Lone Druid does.
* Alchemist is not the kind of hero who wants to go on single target summon units, by the time he has killed the Spirit Bear his teammates might had already been slayed by his teammates. Not to mention Lone Druid can just resummon it, even if he is successful.

* Dispel Magic from {U:Storm} instantly removes Heavenly Grace and Guardian Angel from Omniknight's allies in its radius of effect.

* Global Silence takes Omniknight out of the fight completely.
* Glaives of Wisdom are a great harass vs Omniknight during the laning stages of the game, since it doesn't aggro creeps & ignores his high base armor. It deals pure damage, which means it can also go through Guardian Angel.
* Silencer's intelligence steal can also cause Omniknight to falter in the early phases as it reduces his ability to use his spells.

* Heroes under Guardian Angel can be still damaged from the pure damage of Black Hole and magical damage of Midnight Pulse.

* Arcane Orb's pure damage penetrates Guardian Angel's defense.
* Astral Imprisonment's mana steal is devastating to Omniknight's already low mana pool.

* Guardian Angel is generally useless against Lina as she primarily relies on magical damage. Lina can also dispel it with Eul's Scepter of Divinity as she is a hero who often goes for it. Eul's Scepter of Divinity can later be upgraded into Wind Waker, which will allow Lina to escape from Omniknight.
* Laguna Blade can often finish off Omniknight's allies before he can save them with Purification and Repel. This can become even worse once Lina picks Laguna Blade damage is pure and pierces spell immunity talent, which will allow it to ignore both, any form of spell immunity and Guardian Angel.

* Corrosive Haze followed by Slithereen Crush takes advantage of Alchemist's main weakness, being physical damage before he has the change to improve his surviability with items.
* Bash of the Deep will deal lots of damage during the laning phase.

* Skywrath Mage can easily harass Alchemist in the laning phase with multiple Arcane Bolts. Additionally, if Alchemist is in the process of throwing an Unstable Concoction, and has no way to dispel Ancient Seal, the self stun becomes an easy set up for Mystic Flare.
* Caution, however, as a decently farmed Alchemist with {Item ID:Radiance} and {Item ID:Manta Style} can easily send illusions to harass and force Skywrath Mage out.

* Jakiro's area-of-effect abilities that deal magical damsge make it hard for Omniknight to save multiple enemy heroes at once with Purification and Repel, and Guardian Angel and to harass Omniknight on lane.
* Aghanim's Scepter upgraded Macropyre allows Jakiro to deal pure damage and slow enemy heroes which can pierce debuff immunity, rendering both Repel and Guardian Angel useless.

* Alchemist's reliance on fast attack speed to do single-target damage makes him vulnerable to Static Link. It also goes through Black King Bar, which is a standard item on Alchemist.
* Eye of the Storm is great against high health strength heroes as it reduces their survivability to physical damage.
* Razor has early lane push to counter Acid Spray.

* All of Omniknight's abilities are valuable for Rubick to Spell Steal, and Omniknight has no throwaway ability to cover his last used spell.

* Even though Naga Siren relies on direct attacks to deal damage for most of the time, Song of the Siren allows her to easily waste Guardian Angel.
* Ensnare fully works on targets affected with Heavenly Grace. However, Ensnare is dispellable with any dispel, and so can be dispelled by Heavenly Grace.
* As an agility hero that relies on illusions, Naga Siren is one of the most natural Diffusal Blade carriers, the bane of every hero with a small mana pool. Naga Siren can also buy items that deal magical damage like Radiance, Dagon, Ethereal Blade, Revenant's Brooch, Veil of Discord and Gleipnir to attack Omniknight's allies protected with Guardian Angel.
Additional:
* Although Naga Siren relies mostly on physical damage, Song of the Siren can be used to time out Guardian Angel, giving Naga Siren's team an easy opportunity to counter-initiate.
* Radiance allows it's owner to deal magical damage to multiple enemy heroes at once, and since Naga Siren often buys it, Guardian Angel is not a very good ability for protection against Naga Siren.
* Likewise, Nuker build Naga Siren (which primarly consists of items such as Radiance, Ethereal Blade, Dagon and Veil of Discord) can render Guardian Angel useless. Although Nuker is not a role Naga Siren should be playing.

* Mortimer Kisses can reduce Omniknight's impact in teamfights. Omniknight's Heavenly Grace cannot purge multiple stacks of Mortimer Kisses. The damage is also magical, making Omniknight's ultimate, Guardian Angel, useless.

* Doom applies a basic dispel upon cast, so it can remove Guardian Angel.
* Casting Doom on Omniknight will also prevent him from healing allies with Purification, or casting buffs like Repel and Guardian Angel, basically turning him into a harmless creep.
Additional:
* Doom turns Omniknight into a walking creep, or completely takes out his buffed cores, also removing Heavenly Grace and Guardian Angel in the process.
* With Devour used on Satyr Banisher, Doom will have access to Satyr Banisher's Purge, which will allow him to remove Heavenly Grace and Guardian Angel.

* Doom can disable Chemical Rage's increased healing, rendering Alchemist helpless against Doom.
* Attacks from Infernal Blade can deal serious damage to Alchemist as it deals damage based on the hero's maximum health.

* Heroes with large magical AoE damage will fare well against Omniknight: Lich, Ancient Apparition, Jakiro, Disruptor.

* Visage can quickly kill heroes with low to medium base armor and no innate escape mechanism. Examples include Alchemist, Crystal Maiden and Zeus.

* Heroes that have a weak laning stage: Spectre, Nyx Assassin, Clockwerk, Spirit Breaker, Omniknight, Pudge.

* Heroes who can drain mana can make Omniknight useless after he uses one or two abilities: Lion, Anti-Mage, Nyx Assassin.

* Heroes with long cooldowns on their abilities or ultimate will struggle against the relentless pressure provided by Fiend's Gate: Terrorblade, Dragon Knight, Omniknight.

* Heroes who are entirely reliant on dealing physical damage and/or have very little to no area-of-effect abilities will make Underlord tickle and will have no effect against him thanks to his Atrophy Aura, and will also be unable to ambush Underlord and his team if Underlord chooses to use Fiend's Gate to get to a designated point of the map: Phantom Assassin, Terrorblade, Troll Warlord, Drow Ranger, Phantom Lancer, Chaos Knight, Sven, Wraith King, Bounty Hunter, Alchemist, Templar Assassin, Nyx Assassin, Bane.

* Heroes who can harass Omniknight out of lane will keep him weak in the mid game: Viper, Venomancer, Clinkz.

* Pugna's Decrepify makes sure that either Alchemist is unable to hit anyone while also being slowed and susceptible to magical damage, or can protect an ally from physical attacks. Besides, Pugna can push early on, when Alchemist is not strong enough to repel it, so by the time Alchemist comes online, he might be forced to sit in base.

* Heroes who can drain mana can make Omniknight useless after he uses one or two abilities: Lion, Anti-Mage, Nyx Assassin.

* Heroes who rely on burst physical damage are affected by Lucky Shot's disarm: Terrorblade, Sven, Clinkz, Windranger, Alchemist, Dragon Knight, Legion Commander

* Heroes who can drain mana can make Omniknight useless after he uses one or two abilities: Lion, Anti-Mage, Nyx Assassin.

* Heroes who cannot escape from Trample early might be easy first blood. Heroes like Witch Doctor and Omniknight should play very cautiously alone...

* Heroes that rely on slows or low-duration stuns have trouble catching Weaver: Omniknight, Lich.

* Although Sven relies often on physical damage, an Aghanim's Scepter upgraded Storm Hammer can dispel Guardian Angel with its wide radius.

* Heroes who struggle to fight back against Sven at any point in the game are at a severe disadvantage: Alchemist, Anti-Mage, Crystal Maiden.

* Chemical Rage will rarely save Alchemist against Ursa's Fury Swipes.
* Enrage allows Ursa to both be a threat to Alchemist and avoid his over time damage.

* Reaper's Scythe can kill Alchemist before Chemical Rage has the time to heal him.
* Ghost Shroud can prevent Alchemist from attacking Necrophos, as well as make him immune to Acid Spray and Unstable Concoction damage.
* Heartstopper Aura will do damage as long as Necrophos is alive based on health percentage, which is a problem for a strength hero such as Alchemist.

* Sprout is good for trapping melee carries with no escape abilities: Sven, Alchemist, Lifestealer etc.

* Heroes with large magical AoE damage will fare well against Omniknight: Lich, Ancient Apparition, Jakiro, Disruptor.

* 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.

* Ember's magic damage build is able to burst down Alchemist due to his low strength gain and Alchemist's normal item pick up.

* Tidebringer will deal lots of damage to Alchemist before he builds physical survivability items.
* Torrent and X Marks the Spot can control Alchemist at all stages of the game before he has Black King Bar.
* Ghostship's rum buff will greatly reduce the Alchemist's damage output in teamfights including his Radiance.

* Melee heroes that get kited easily have hard times dealing with Puck without any lockdowns, as Puck is one of the most mobile heroes. Heroes like Sven, Lifestealer, Ursa and Alchemist may have problems to get to Puck without proper initiation items. They also lack reliable lockdowns, as their disables are easily avoidable for Puck, or are just a soft disable.

* Axe can force Alchemist to attack him with Berserker's Call. High attack speed from Chemical Rage will cause Counter Helix to proc multiple times.
* This can get worse if axe has Blade Mail, which then returns all damage to Alchemist himself.
* Axe's abilities can pierce through Black King Bar, which is a common item for Alchemist.
* Berserker's Call grants Axe a huge bonus armor, which greatly counters Alchemist's physical damage for the most part.