* Squishy core heroes (Shadow Fiend, Sniper, etc)

* Heroes with AoE abilities are a bane to Beastmaster's summons: Storm Spirit, Magnus, Pangolier.

* Heroes with channeling spells because Shadow Fiend has nothing to cancel channeling outside of Requiem of Souls: Bane, Enigma, Pudge, Shadow Shaman, Dawnbreaker, Warlock, Crystal Maiden.

* Heroes with summoned units don't fare well against Dawnbreaker. (Phantom Lancer ,Beastmaster ,Lycan)

* Heroes that are hard to kill without lockdown: Puck, Weaver.

* Heroes with Linken's Sphere as core item: Weaver, Morphling, Medusa.

* Static Link can steal Shadow Fiend's high physical damage output from Necromastery, lowering his damage output, and Static Link cannot be prevented by Black King Bar.
* Plasma Field and Eye of the Storm can melt down Shadow Fiend easily, due to his low health.

* False Promise effectively nullifies Primal Roar's single-target initiation on allies.
* Purifying Flames kills Beastmaster's Hawk instantly and Boar with two casts.

* Bounty Hunter can absolutely destroy a Shadow Fiend's game by ganking his midlane with Shadow Walk, Jinada and Shuriken Toss.
* If his lane goes bad, a Shadow Fiend usually goes to the jungle. Follow him with Shadow Walk and take half of his experience.
* Due to its ministun, Shuriken Toss is a good way to interrupt Shadow Fiend's long cast animation on Requiem of Souls.
Additional:
* Shuriken Toss can be used to cancel Requiem of Souls.
* Shadow Walk and Jinada allow Bounty Hunter to gank Shadow Fiend early on
* Track prevents Shadow Fiend from escaping with Shadow Blade.

* Having many summons out will cause Echo Slam to deal extra damage.

* 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.
Additional:
* 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.

* Shadow Fiend, a normal Shadow Blade builder often relies on its invisibility to escape fights. Corrosive Haze reveals Shadow Fiend and also weakens his already low armor.

* Lucent Beam and Eclipse with ministun talent can be used to cancel Requiem of Souls if Shadow Fiend does not have Black King Bar. Likewise, since Shadow Fiend is prone to buying Blink Dagger, an ill-timed Blink Dagger can give Luna a free chance to counter-initiate with Eclipse.
* Moon Glaives and Lunar Blessing allow Luna to outfarm Shadow Fiend in lane and the high physical damage output they provide her can also help her deal with Shadow Fiend even when he buys Black King Bar in late game.
* A well timed Eclipse will burst and kill Shadow Fiend before he even either initiates or gets a chance to retaliate, especially when equipped with Aghanim's Scepter and Ethereal Blade, this could become even worse for Shadow Fiend if he does not have Black King Bar. But bear in mind however, that smart and skilled Shadow Fiend can buy Wind Waker to counter this issue.
* Even though Shadow Fiend can evade all of Luna's abilities with Shadow Blade, a smart Luna will always buy Dust of Appearance to provide vision on Shadow Fiend to her and her team.
Additional:
* Lucent Beam and Eclipse with ministun talent can be used to cancel Requiem of Souls if Shadow Fiend does not have Black King Bar. Likewise, since Shadow Fiend is prone to buying Blink Dagger, an ill-timed Blink Dagger can give Luna a free chance to counter-initiate with Eclipse.
* Moon Glaives and Lunar Blessing allow Luna to outfarm Shadow Fiend in lane and the high physical damage output they provide her can also help her deal with Shadow Fiend even when he buys Black King Bar in late game.
* A well timed Eclipse will burst and kill Shadow Fiend before he even either initiates or gets a chance to retaliate, especially when equipped with Aghanim's Scepter and Ethereal Blade, this could become even worse for Shadow Fiend if he does not have Black King Bar. But bear in mind however, that smart and skilled Shadow Fiend can buy Wind Waker to counter this issue.
* Even though Shadow Fiend can evade all of Luna's abilities with Shadow Blade, a smart Luna will always buy Dust of Appearance to provide vision on Shadow Fiend to her and her team.

* Berserker's Call and Counter Helix allow Axe to kill Shadow Fiend if he stands too close to a creep wave.
* Battle Hunger is very strong against Shadow Fiend in the early game because Shadow Fiend's low attack damage makes it hard for him to get last hits.
* Axe's naturally high strength and health regeneration will be enough to tank a lot of Shadow Fiend's damage in the early game.

* Shadow Fiend's lack of mobility and low base health make him an easy target for early ganks.

* 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.

* Heroes with channeling spells because Shadow Fiend has nothing to cancel channeling outside of Requiem of Souls: Bane, Enigma, Pudge, Shadow Shaman, Dawnbreaker, Warlock, Crystal Maiden.

* 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.

* Illuminate clears Beastmaster's summons and is effective against his push.

* Kraken Shell dispels both Shadowraze's damage amplification stacks and Requiem of Soul's damage reduction (provided Tidehunter has taken enough damage).
* Ravage cancels Requiem of Souls if Shadow Fiend isn't protected by Black King Bar.
Additional:
* Kraken Shell dispels the damage amplification stacks of Shadowraze as well as the damage reduction from Requiem of Souls (provided he has taken enough damage).
* Anchor Smash reduces Shadow Fiend's large attack damage, Kraken Shell makes Tidehunter the last target Shadow Fiend wants to attack.
* Ravage can easily cancel Requiem of Souls if Shadow Fiend isn't protected by Black King Bar.

* Charge of Darkness allows Spirit Breaker to gank Shadow Fiend in the early game, preventing him from getting Necromastery stacks.
* Nether Strike and Charge of Darkness can be used to prevent Shadow Fiend from casting Requiem of Souls.

* Glimpse and Kinetic Field allows Disruptor to set up some early kills onto Shadow Fiend.
* Static Storm can be used to cancel the cast of Requiem of Souls.

* 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.

* Enfeeble can be used to decrease Shadow Fiend's already abysmal level one damage even further, preventing him from getting farm and Necromastery stacks.
* Brain Sap allows Bane to heavily harass Shadow Fiend.
* Nightmare allows Bane to set up some early ganks onto Shadow Fiend.
* Fiend's Grip enables Bane to completely take Shadow Fiend out of a fight and potentially even kill him, even through Black King Bar.
Additional:
* Enfeeble can be used to decrease Shadow Fiend's already abysmal level one damage even further, preventing him from getting farm and Necromastery stacks.
* Brain Sap allows Bane to heavily harass Shadow Fiend.
* Nightmare allows Bane to set up some early ganks onto Shadow Fiend.
* Fiend's Grip enables Bane to completely take Shadow Fiend out of a fight and potentially even kill him, even through Black King Bar.

* Decrepify prevents Shadow Fiend from attacking for its duration, potentially preventing him from getting a kill.
* Nether Ward can do heavy damage to Shadow Fiend if he tries to cast his Requiem of Souls and his Shadowraze.
Additional:
* Decrepify prevents Shadow Fiend from attacking for its duration, potentially preventing him from getting a kill.
* Nether Ward can do heavy damage to Shadow Fiend if he tries to cast his Requiem of Souls or spam Shadowraze.

* Shadow Fiend's Requiem of Souls allows Rubick to output enormous crowd damage and control to the enemy team.
* Requiem of Souls has an effective range of 1000. Rubick can steal the spell out of the fear range with any level of Arcane Supremacy learned.
* Requiem of Souls has a significant cast animation which allows Rubick to predict the steal timing, since Shadow Fiend usually positions at the center of battlefield.
* Telekinesis can lift a unit right on top of Rubick with no collision size, forcing the victim to absorb all damaging lines of Requiem of Souls from Rubick, possibly resulting in a one-shot kill.
* Note that Requiem of Souls from Rubick still uses the original 1.67 second channeling time.
* It is advised to build Blink Dagger to jump in and cast Requiem of Souls given the opportunity.
* The three Shadowraze (Far) abilities are decent for farming and extra damage output.
* Note that Shadowraze (Near), Shadowraze (Medium) and Shadowraze (Far) are considered three separated abilities, only one is stolen per spell steal cast.
* It could be troublesome to cast Shadowraze (Far) immediately for damage output immediately after stolen since it is hard to react and recognize which of the three is stolen.
* Shadow Fiend's right click damage together with his ability damage may hurt Rubick bad. Consider items like Ghost Scepter and Glimmer Cape, together with wards to avoid being picked up.

* Doom has several disable abilities to choose from jungle creeps (e.g. War Stomp, Ensnare) to deal with Shadow Fiend who lacks escape abilities.
* When Doom combines creep abilities with Scorched Earth, Infernal Blade, and Doom, Shadow Fiend most likely will die as he cannot use Shadowraze and Requiem of Souls to protect himself, and also cannot even flee by using Shadow Blade or Blink Dagger.
* Although Shadow Fiend has a high physical damage output, Doom has a large health pool to survive it, meaning Doom's combo with high magical damage output will shutdown Shadow Fiend first.
* Doom usually buys Radiance to improve his damage, making his nuke combo more deadly to Shadow Fiend. The blind also prevents Shadow Fiend from landing his attacks often.

* 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.

* 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, mitigating his effectiveness during the laning stage and teamfights.

* The Reflection of Shadow Fiend cause Presence of the Dark Lord to affect Shadow Fiend, reducing his armor and making it easier for Terrorblade to kill him. Shadow Fiend also doesn't have lots of survivability or control abilities in order to escape.
* If Shadow Fiend chooses to go for a physical damage item build, he'll have a hard time against Terrorblade's high armor.

* Shrapnel can be used to cancel Shadow Fiend's Blink Dagger from a huge range.
* Take Aim and Headshot allow Sniper to harass Shadow Fiend in lane without getting into the range of his Shadowrazes.
Additional:
* Shrapnel can be used to cancel Shadow Fiend's Blink Dagger from a huge range.
* Take Aim and Headshot allow Sniper to harass Shadow Fiend in lane without getting into the range of his Shadowraze.
* Assassinate when upgraded with Aghanim's Scepter can be used to cancel Shadow Fiend's Requiem of Souls.

* Heroes that can gank Shadow Fiend in the early game: Earth Spirit, Nyx Assassin, Riki, Spirit Breaker.

* 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

* Heroes with channeling spells are very easy targets for Jakiro's abilities: Crystal Maiden, Dawnbreaker, Enigma, Pudge, Shadow Fiend, Shadow Shaman, Warlock.

* Heroes with channeling spells because Shadow Fiend has nothing to cancel channeling outside of Requiem of Souls: Bane, Enigma, Pudge, Shadow Shaman, Dawnbreaker, Warlock, Crystal Maiden.

Additional:
* Because Shadow Fiend lacks escaping mechanisms, and is dependent on fair positioning for channeling Requiem of Souls, it's easier for Warlock with his long range crowd control abilities to lock Shadow Fiend down for his team.

* Heroes that have small health pools and little to no escape mechanisms are even easier prey for Necrophos. Ghost Shroud's slow will allow him to catch him with them, and get nuked down with his abilities, even preventing retaliation due to Reaper's Scythe's stun. Such heroes include Crystal Maiden, Witch Doctor, Warlock or Shadow Fiend.

* Heroes with high burst damage: Lina, Lion, Luna, Nyx Assassin, Queen of Pain.

* Large area-of-effect with delay or require channeling: Enigma, Crystal Maiden, Invoker, Shadow Fiend, Pugna, Keeper of the Light, Dawnbreaker.

* Heroes who summon multiple units that are not spell immune. Nature's Prophet,Lycan,Beastmaster

* Heroes that can gank Shadow Fiend in the early game: Earth Spirit, Nyx Assassin, Riki, Spirit Breaker.

* Heroes with channeling spells because Shadow Fiend has nothing to cancel channeling outside of Requiem of Souls: Bane, Enigma, Pudge, Shadow Shaman, Dawnbreaker, Warlock, Crystal Maiden.

* Heroes with channeling spells because Shadow Fiend has nothing to cancel channeling outside of Requiem of Souls: Bane, Enigma, Pudge, Shadow Shaman, Dawnbreaker, Warlock, Crystal Maiden.

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

* Heroes with AoE abilities are a bane to Beastmaster's summons: Storm Spirit, Magnus, Pangolier.

* Heroes that are hard to kill without lockdown: Puck, Weaver.

* Heroes with long animations can be frequently interrupted with Cold Snap: Earthshaker, Monkey King, Shadow Fiend Lina

* Single-target disablers will have difficulty locking down a Chaos Knight with Phantasm active: Bane, Beastmaster, Bloodseeker, Clockwerk, Doom, Shadow Shaman.

* Heroes with high physical damage output but lack of reliable escape mechanisms are always a good target for a solo gank: Sniper, Shadow Fiend, Troll Warlord, Drow Ranger. Those heroes, however, are dangerous if they manage to close the gap, so take caution.

* Heroes with Linken's Sphere as core item: Weaver, Morphling, Medusa.

* Heroes with high burst damage: Lina, Lion, Luna, Nyx Assassin, Queen of Pain.

* Heroes with Linken's Sphere as core item: Weaver, Morphling, Medusa.

* Void can be used to cancel Requiem of Souls.
* Crippling Fear prevents Shadow Fiend from using Shadowraze or Requiem of Souls.
* With Dark Ascension and Gem of True Sight, Night Stalker can find and kill Shadow Fiend easily. He is also a tanky hero that can fight Shadow Fiend at any stage of the game.

* Chen can take control of the Boar from Call of the wild Boar at any time.

* Nethertoxin breaks both Necromastery and Presence of the Dark Lord, reducing his damage massively.
* Corrosive Skin gives Viper bonus Magic Resistance against Shadowraze and Requiem of Souls.
* Viper can easily take advantage of Shadow Fiend's lack of escape and mobility spells with Viper Strike and Poison Attack. Poison Attack also serves as a great way to harass Shadow Fiend.

* Dragon Tail can be used to cancel Requiem of Souls.
* Breathe Fire reduces Shadow Fiend's damage even further.
* Dragon Knight's high strength and Dragon Blood means that he'll be able to tank Shadow Fiend's right clicks.