* 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.

* 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.

* Heroes who depend on attacks (such as Shadow Fiend or Drow Ranger) can be nullified by Fire Spirits' attack speed slow.

* Fire Spirits greatly reduces Slardar's already low starting attack speed (which Bash of the Deep relies on), making the laning phase very hard for him and discouraging Slardar from aggressively threatening lane kills.
* Supernova, ignoring Phoenix's lack of armor and Slardar's high damage single hits, is extremely hard for Slardar to take down on his own, especially after being hit by Fire Spirits.
* Icarus Dive is one of the longest distance escape spells in the game, and can help a good Phoenix escape from Slardar before he gets a Blink Dagger. However, the high cooldown means Phoenix is vulnerable to backstabs from any roamers after said spell is used.
* Slardar can interrupt an Icarus Dive from completing the flight with both of his stuns, however, likely leading to death if Supernova is on cooldown.
* A lot of the items a Phoenix builds throughout the game naturally counter Slardar. Shiva's Guard, Heaven's Halberd and Eul's Scepter of Divinity all stall Slardar's normal attacks in some way, while Spirit Vessel's percentage-based damage is good against his innate durability.

* 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.

* Illusion heroes like the aforementioned Phantom Lancer or Naga Siren, or heroes that tend to buy Manta Style, like Luna or Juggernaut, will give Slardar a hard time, as his damage is single-targeted.

* 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.

* Tidehunter's Kraken Shell dispels Corrosive Haze and Bash of the Deep's stun if enough damage is taken. Anchor Smash and Kraken Shell's damage block also reduces Slardar's damage.

* 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.

* Terrorblade starts out with and gains a lot of armor from his agility growth. His illusions also make it difficult for Slardar to focus down the real Terrorblade.

* 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.

* Enigma can be a perfect counter-initiator with his ultimate. A perfectly timed Black Hole will turn the tide of any initiation, especially from heroes like; Spirit Breaker, Legion Commander, Axe, Puck, and Slardar

* The blind from Laser prevents Shadow Fiend from attacking for its duration, potentially preventing him from getting a kill.
* Scythe of Vyse can be used to prevent Shadow Fiend from casting Requiem of Souls.
* A combination of Tinker's abilities and his items (like the Dagon 5 and Ethereal Blade combo) can kill Shadow Fiend quickly.
Additional:
* During the laning stage Laser will reduce Shadow Fiend's last hits, preventing him from getting Necromastery souls.
* Shadow Fiend has low health and is vulnerable to Tinker's high magic burst.

* 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.

* 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.

* Fortune's End applies a basic dispel which can be used to dispel Corrosive Haze, or even Slardar's own Guardian Sprint.
* False Promise is able to dispel Corrosive Haze and Slithereen Crush stun/slow from any allies Oracle chooses to cast it on.
* Fate's Edict can also be cast on Slardar to prevent him from proccing his Bash of the Deep.

* Abaddon can cast Aphotic Shield on any of his allies to immediately dispel Corrosive Haze and/or the stun and the slow components of Slithereen Crush.
* All of Slardar's debuffs are also removed if Abaddon's Borrowed Time triggers.

* Phantom Lancer's Doppelganger has a low cooldown and applies a basic dispel on PL, making it hard to keep Corrosive Haze on him.
* Phantom Lancer usually purchases Manta Style which provides another basic dispel to remove Corrosive Haze with.
* Besides Slithereen Crush, Slardar does not have another way to deal with illusions and has a low mana pool, which allows Phantom Lancer with Diffusal Blade to quickly build up illusions while draining Slardar's mana.
* Phantom Rush outruns Guardian Sprint, forcing Slardar to Blink away or use Slithereen Crush defensively to avoid being killed.

* 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.

* 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.

* 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.

* 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.

* Requiem of Souls is easily interrupted by Boundless Strike, due to its long cast time.
* Shadow Fiend's lack of mobility and escape makes him an easy target to ambush with Primal Spring, especially during laning stage.
* Being close means he cannot use all three razes on you before you get your Jingu Mastery stacks.

* 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.

* Illusion heroes like the aforementioned Phantom Lancer or Naga Siren, or heroes that tend to buy Manta Style, like Luna or Juggernaut, will give Slardar a hard time, as his damage is single-targeted.

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

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

* 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 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 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.

* Illusion heroes like the aforementioned Phantom Lancer or Naga Siren, or heroes that tend to buy Manta Style, like Luna or Juggernaut, will give Slardar a hard time, as his damage is single-targeted.

* 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.

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

* Bloodseeker's Rupture forces Slardar to stay still during fights, preventing Slardar from using Guardian sprint to move in and out of fights. This takes away the ability to initiate and re-initiate with Slithereen Crush's low cooldown. Due to the increased move speed from Guardian Sprint, Slardar can lose health at about 160% the rate of normal heroes while under Rupture. Bloodseeker's Thirst also gives him enough move speed so that he's one of the few heroes who can outrun or catch up to a Slardar during Guardian Sprint.

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

* Late game heroes are Sven's favourite kind of opponent, such as Anti-Mage, Spectre and Shadow Fiend.

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

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

* Shadow Fiend's fragility and lack of a natural escape mechanism makes him a great target for Templar Assassin's Meld.
* Shadow Fiend's burst damage, such as Shadowraze and Requiem of Souls, is easily nullified by her Refraction.