* 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.

* Warlock's signature Chaotic Offering can be devastating if stolen and dropped on multiple heroes.
* Telekinesis interrupts Upheaval when used on Warlock. Alternatively, Rubick can also cast this on a naerby creep or hero and drop them near Warlock to interrupt its channeling. When upgraded with Aghanim's Shard, Rubick can also use it to save an ally (or himself) from its area slow and damage.
* Fatal Bonds provides Rubick with a decent farming and harassing tool in the early game.
* Shadow Word provides some utility by healing Rubick and his team, and also as a harassment tool when used on enemies in the laning stage.
* Upheaval slows and damages enemies in an area, and it works exactly the same when casted by Rubick. Furthermore, he can extend its range and debuff amplification with Arcane Supremacy.
* A stolen Chaotic Offering can also be used to interrupt Upheaval while Telekinesis is on cooldown.
* It is advised to build items around Chaotic Offering as Rubick. Aghanim's Scepter, Octarine Core and Refresher Orb are all legitimate item choices.
Additional:
* All of Warlock's abilities are worthy choices for Rubick to Spell Steal, primarily Chaotic Offering. Furthermore, stolen abilities are also affected by the increased cast range and spell amplification from Arcane Supremacy.
* Telekinesis interrupts Upheaval when casted on Warlock, or to save allies (or himself) from its area slow and damage with Aghanim's Shard.
* Bear in mind that Warlock likes to cast his abilities in quick succession, so the time window left for Rubick to steal Warlock's ultimate can be short.

* 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

* Mana Break prevents Warlock from casting his spells, particularly in the laning phase.
* Blink allows Anti-Mage to escape from Upheaval.
* Counterspell reduces damage from Shadow Word and Warlock's Golem's Permanent Immolation passive. Additionally, it can reflect Shadow Word and Fatal Bonds.
* Mana Void deals heavy damage after Anti-Mage has drained Warlock's large mana pool.

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

* Impale and Spiked Carapace interrupts Upheaval with ease.
* Warlock's low health pool, mobility, and high intelligence gain makes him a prime target for Nyx Assassin's burst damage.

* Earthshock prevents Shadow Fiend from escaping after Ursa used his Blink Dagger to get on top of him.
* Overpower and Fury Swipes allow Ursa to quickly kill Shadow Fiend.
* Enrage keeps Ursa alive in a manfight with Shadow Fiend and allows him to stay close, even if Shadow Fiend uses Requiem of Souls.

* Ursa can shred Warlock's Golems in a few seconds with Fury Swipes and Overpower.

* Despite Jakiro's fragileness, he can easily harass Shadow Fiend with Dual Breath and Liquid Fire than Shadow Fiend can harass Jakiro with Shadowraze.
* Jakiro can easily cancel Requiem of Souls with Ice Path as Shadow Fiend is a very easy target while channeling it.
* Aghanim's Scepter upgraded Macropyre can deal pure damage-over-time and pierce spell immunity, which can discourage Shadow Fiend from even trying to initiate with Requiem of Souls.
Additional:
* Despite Jakiro's fragileness, he can easily harass Shadow Fiend with Dual Breath and Liquid Fire than Shadow Fiend can harass Jakiro with Shadowraze.
* Jakiro can easily cancel Requiem of Souls with Ice Path as Shadow Fiend is a very easy target while channeling it.
* Aghanim's Scepter upgraded Macropyre can deal pure damage-over-time and pierce spell immunity, which can discourage Shadow Fiend from even trying to initiate with Requiem of Souls.

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

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

* Weaver's Shukuchi allows him to escape from Warlock's Upheaval with high move speed.
* Time Lapse allows Weaver to ignore damage from Warlock's Golem and escape.

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

* With God's Strength, Warlock's Golem from Chaotic Offering will go down in a matter of seconds. The two weaker golems granted by Aghanim's Scepter will fare worse due to Great Cleave hitting both.
* Aghanim's Scepter upgraded Storm Hammer Aghanim's Scepter can dispel Shadow Word.
Additional:
* God's Strength combined with Great Cleave destroys Chaotic Offering golems within seconds.
* Warcry gives Sven and his allies armor to help against Warlock's Golem's heavy physical damage and movement speed to help escape Upheaval.
* Storm Hammer disrupts Upheaval.

* 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.

* Supports with useful teamfight or contribution spells will be helpless against Doom: Dazzle, Oracle, Warlock.

Additional:
* Doom will not only prevent Warlock from casting his abilities in team fights, but also it reduces the healing from Shadow Word.
* Devour allows Doom to acquire a stun from neutral creeps, allowing him to interrupt Upheaval without having to use Doom.

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

* Because all of Warlock's abilities are active abilities, silences can make his impact in fights minimal. Be cautious of heroes that carry silences like Death Prophet, Puck, and the aforementioned Silencer.

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

* Warlock is a very strong hero when positioned correctly, and his long cast range helps him with this. However, some heroes might disrupt or sneakily pass through his allies and deal with him, preventing him from doing his job. Such heroes include Chaos Knight, Spirit Breaker, Riki, and more.

* Ice Blast cancels Warlock's Golem's and Shadow Word's healing.
* Cold Feet stuns Warlock if he stands in place, forcing him to stop channeling Upheaval immediately or be forced to stop channeling it by it's stun.

* 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.

* 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.

* Fragile supports with low armor are always a good prey, also her Psionic Trap will wear down most attempts to flee with their built-in disables: Silencer, Crystal Maiden, Warlock, Ancient Apparition, Grimstroke, Witch Doctor

* 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.

* Shapeshift allows Lycan to escape from Upheaval with maximum movement speed.
* Warlock doesn't have a good solution to deal with Lycan's wolves from Summon Wolves.

* 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.

* 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.

* 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.

* Berserker's Call and Counter Helix allow Axe to kill Shadow Fiend if he stands too close to a creep wave.
* Battle Hunger is can be strong against Shadow Fiend in the early game because Shadow Fiend's low attack damage makes it hard for him to get last hits if he has no mana. However, Shadowraze also makes it very easy for him to get last hits, so use with caution.
* Axe's naturally high strength and health regeneration will be enough to tank a lot of Shadow Fiend's damage in the early game.

* 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.

* 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.

* 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.

* Warlock is a very strong hero when positioned correctly, and his long cast range helps him with this. However, some heroes might disrupt or sneakily pass through his allies and deal with him, preventing him from doing his job. Such heroes include Chaos Knight, Spirit Breaker, Riki, and more.

* Ghostship helps your team soak up damage from Chaotic Offering and hit summons hard.
* Tidebringer clears summons later in the game.
* Most of your spells can interrupt Upheaval.

* 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.

* 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.

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

* 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.

* 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.

* 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, 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.

* Lina can outlanes Shadow Fiend on the central line, due to the fact that Lina's attack range exceeds the attack range of Shadow Fiend, which makes it difficult for him to fend off her attacks and approach creeps, thus Lina has more level and gold.
* Lina can defeat Shadow Fiend with the combination of her abilities on lane and during teamfights: Light Strike Array, Dragon Slave, Laguna Blade, Shadow Fiend does not have a large pool of health before buying items for extra strength and health like Satanic, which is why Lina's strong magic damage is enough to kill him quickly.
Additional:
* Outlanes Shadow Fiend on the central line, due to the fact that Lina's attack range exceeds the range of Shadow Fiend, which makes it difficult for him to fend off her attacks and approach creeps, thus Lina has more level and gold
* Defeats Shadow Fiend` from Burst with a combination of skills: Light Strike Array, Dragon Slave, Laguna Blade, Shadow Fiend does not have a large pool of health before buying an item: Satanic , which is why Lina's strong magic damage is enough to kill him quickly

* 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 rely on summons will suffer against Ion Shell, which kills them very quickly: Beastmaster, Broodmother, Enigma, Nature's Prophet, Visage, Warlock, Wraith King.

Additional:
* Surge allows for Dark Seer and his allies to escape from Upheaval due to it ignoring any slow.

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

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

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

* Heroes who rely on summons will see them destroyed easily by Overwhelming Odds: Lycan, Arc Warden, Warlock, Chen

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

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

* 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.

* Warlock is a very strong hero when positioned correctly, and his long cast range helps him with this. However, some heroes might disrupt or sneakily pass through his allies and deal with him, preventing him from doing his job. Such heroes include Chaos Knight, Spirit Breaker, Riki, and more.

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

* 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, even through debuff immunity from Black King Bar.
* 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.

* 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.

* Nethertoxin 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 breaks and Poison Attack. Poison Attack also serves as a great way to harass Shadow Fiend.

* 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.

* Because all of Warlock's abilities are active abilities, silences can make his impact in fights minimal. Be cautious of heroes that carry silences like Death Prophet, Puck, and the aforementioned Silencer.

* 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.

* A pre-placed Fire Remnant allows Ember Spirit to escape Upheaval.
* Flame Guard blocks Shadow Word's damage.
* Sleight of Fist allows Ember Spirit to attack from outside of Upheaval's range, and Searing Chains lets him interrupt it.

* 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.

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

* Because Warlock's abilities are all active abilities, Silencer can make his impact minimal.
* Arcane Curse prevents Warlock from using his abilities without increasing it's duration, which since all of Warlock's abilities are actives it is very effective against him.
* Last Word can prevent Warlock from casting his Fatal Bonds, Chaotic Offering, and Upheaval combo.
* Global Silence can nullify Warlock's impact in fights by preventing him from casting Fatal Bonds and Chaotic Offering, or by interrupting his Upheaval.