* With armor items like Solar Crest or Assault Cuirass combined with Bash of the Deep, Slardar can easily tank the Duel, If not dueled himself, he can drop Legion Commander's armor during duel and/or buff his teammate and save them, leaving her only the choice of dueling supports which can also be saved with fast Blink into Slithereen Crush.

* Atrophy Aura's percentage-based damage reduction greatly diminishes Legion Commander's overall damage output, even if she has won many Duels
* Legion Commander cannot get out the way of Firestorm because she is stationary.
Additional:
* Atrophy Aura makes it hard for Legion Commander to win Duels.
* Fiend's Gate can be used to save Underlord and his allies from a Duel or to intercept Legion Commander, because outside from Overwhelming Odds, Legion Commander has no other area-of-effect abilities.

* Corrosive Haze works much like Track, giving the enemy team vision over Riki. While it doesn't give a movement speed or gold bonus, it instead can melt Riki's armor and Slardar can use Guardian Sprint to catch up to him.
* Slardar's Aghanim's Shard, causes Slithereen Crush to apply Corrosive Haze even if Slardar does not have vision over him.
Additional:
* Corrosive Haze makes Riki completely vulnerable to Slardar and his allies, as Riki has no easy way of dispelling it.
* Slardar's physical damage with Slithereen Crush and Bash of the Deep amplified by Corrosive Haze can easily kill Riki.

* Pit of Malice prevents Riki from casting Blink Strike. or Tricks of the Trade.
* Atrophy Aura reduces Riki's damage.
* Firestorm can be used to harrass Riki in lane.

* Heroes who can provide True Sight or semi-reveal enemy heroes as Nature's Prophet is prone to buying Shadow Blade: Bounty Hunter, Slardar, Spectre, Spirit Breaker.

* Firestorm makes quick work of Treants and Atrophy Aura gives him temporary damage for every Treant killed.
* Pit of Malice can stop Teleportation channeling.
* Atrophy Aura greatly reduces Nature's Prophet's damage and he has no other good way to deal damage.
* Fiend's Gate can counter split-pushing, which is something that Nature's Prophet relies on a lot.

* 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.

* In general, attacks of the melee 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, and will be unable to ambush Underlord and his team if Underlord chooses to use Dark Rift 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.

* Corrosive Haze hinders Nyx Assassin's ganking attempts with Vendetta, as well as reducing his armor and make him very vulnerable due to his low health pool.

* In general, attacks of the melee 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, and will be unable to ambush Underlord and his team if Underlord chooses to use Dark Rift 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.

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

* 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.

* Corrosive Haze provides True Sight on its target, exposing Bounty Hunter's position regardless of Shadow Walk.
* Guardian Sprint gives a very high movement speed bonus, allowing him to chase Bounty Hunter even if Slardar is tracked.
Additional:
* Bounty Hunter's Shadow Walk is rendered useless with Corrosive Haze and makes Bounty Hunter an easy target for Slardar and his team.

* In general, attacks of the melee 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, and will be unable to ambush Underlord and his team if Underlord chooses to use Dark Rift 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.

* Slardar can chase Dragon Knight down with Guardian Sprint and stun him with both Slithereen Crush and his passive Bash of the Deep. He can also use Corrosive Haze to whittle Dragon Knight's armor.

* In general, heroes with long cooldowns on their abilities or ultimate will struggle against the relentless pressure provided by Dark Rift or Fiend's Gate (Requires Aghanim's Scepter): Terrorblade, Dragon Knight, Omniknight.

* Slardar's level 25 talent makes Corrosive Haze undispellable, thus providing his allies vision of Slark.

* Heroes with AoE abilities will hit Slark in Shadow Dance: Lina, Jakiro, Underlord, Leshrac, Dark Seer, Earthshaker, Timbersaw, Crystal Maiden.

* Guardian Sprint allows Slardar to outrun Bristleback, even when slowed by Viscous Nasal Goo.
* Corrosive Haze's armor reduction makes Bristleback much less tanky.

* Firestorm and Pit of Malice are very disruptive in team fights, completely matching Mars especially since it can all be cast inside Arena Of Blood and also does percentage-based magical damage, negating Bulwark.
* Dark Rift can save any allies of Underlord trapped in Arena Of Blood.
* Atrophy Aura allows Underlord to lane against Mars quite well since he does not have the best base damage during the early game.
* Underlord is a common carrier of both Pipe of Insight and Mekansm/Guardian Greaves, allowing his team to combat Mars in the mid to late game.

* Pit of Malice prevents Phantom Assassin from either escaping or engaging with Phantom Strike.
* Phantom Assassin's damage output is entirely physical, therefore Atrophy Aura Atrophy Aura is very hazardous for her in most of the stages, particularly since it also affects Coup De Grace Coup de Grace, hindering Phantom Assassin's main source of damage.
* Without proper items and any area-of-effect ability/item, Phantom Assassin cannot stop Underlord and his team to escape with Fiend's Gate, nor she can intercept them if Underlord chooses to teleport on any area of the map.
Additional:
* Pit of Malice prevents Phantom Assassin from either escaping or engaging with Phantom Strike.
* Phantom Assassin's damage output is entirely physical, therefore Atrophy Aura Atrophy Aura is very hazardous for her in most of the stages, particularly since it also affects Coup De Grace Coup de Grace, hindering Phantom Assassin's main source of damage.
* Without proper items and any area-of-effect ability/item, Phantom Assassin cannot stop Underlord and his team to escape with Fiend's Gate, nor she can intercept them if Underlord chooses to teleport on any area of the map.

* Heroes who can provide True Sight are always credible threats: Slardar, Bounty Hunter, especially Zeus since his Lightning Bolt provides True Sight without the need to detect her beforehand to apply the debuff. So even a late-coming Zeus can easily scout a large area to reveal her, and she cannot purge herself from his sight with the dispel talent.

* Firestorm will destroy Refraction charges very quickly.
* Firestorm will hit Templar Assassin while under the effects of Meld Meld.
* Templar Assassin has a hard time maneuvering around Pit of Malice.

* The brutal physical damage of Slithereen Crush and Bash of the Deep can quickly remove Void Spirit's shield and stun him for a while.
* Corrosive Haze provides vision of Void Spirit while he is running away and Guardian Sprint allows Slardar to quickly close the gap

* Pit of Malice can be cast in the path of Spirit Breaker's Charge of Darkness to cancel it.
* Dark Rift provides a way to escape from a gank for Underlord and his teammates.

* Corrosive Haze reveals Pudge's location, making it hard for him to use Meat Hook from the fog of war on Slardar's teammates or Slardar himself.
* Slithereen Crush interrupts Pudge while he is using Dismember.
* Guardian Sprint allows Slardar to avoid Meat Hook.
Additional:
* While Slardar has Guardian Sprint activated, Rot cannot slow him and Meat Hook is easier to avoid.
* Slithereen Crush allows Slardar to interrupt Dismember at close range (when Slardar is not a target).
* Corrosive Haze reveals Pudge's location, making it very difficult for him to land hooks from the fog.

* Atrophy Aura decreases Troll Warlord's damage.
* Pit of Malice helps lock down Troll Warlord.
* Battle Trance disallows Troll from running out of both Firestorm and Pit of Malice.

* Weaver relies on Shukuchi to escape and kite enemy heroes. Slardar's Corrosive Haze lowers armor and reveals Weaver, who is already a very frail target.
* Weaver usually builds Linken's Sphere, Corrosive Haze can be used to pop the spell block, additionally the level 25 undispellable talent will prevent Weaver from removing Corrosive Haze with Time Lapse, allowing allied heroes to use their abilities on Weaver.
Additional:
* Corrosive Haze lowers armor and reveals Weaver during Shukuchi, who is already a frail target. In addition, Weaver usually builds Linken's Sphere, and Corrosive Haze can be used to "pop" the spell block. His level 25 talent can also make Corrosive Haze undispellable by Time Lapse, which puts Weaver in an even worse situation.
* Guardian Sprint can dodge Weaver's bugs with the movement speed bonus.

* Atrophy Aura reduces Drow Ranger's damage significantly, as she relies on agility to be effective.

* Firestorm will easily clear Chen's creeps.
* Pit of Malice will trap Chen and render him helpless.
* Atrophy Aura gives bonus damage to Underlord for each killed creep and weakens Chen's damage.
* Fiend's Gate can counter Chen's pushing attempts, and he has nothing to intercept it.

* Slardar can reveal Clinkz with Corrosive Haze and make him easy to kill, and his Bash of the Deep also hits hard against Clinkz's naturally low health pool.
* Slardar's Guardian Sprint can catch up with Clinkz's Skeleton Walk.
* The stun and slow from Slardar's Slithereen Crush can hold Clinkz in place.
Additional:
* Clinkz survivability depends entirely on Skeleton Walk. Corrosive Haze not only makes its invisibility useless, but also makes Clinkz even more vulnerable to physical damage.

* Corrosive Haze and Bash of the Deep will make short work of Huskar's low armor, even if Slardar is alone.

* Slardar deals entirely physical damage.He needs not worry about Counterspell.
* Slithereen Crush and Bash of the Deep prevent Anti-Mage from using Blink, the latter even if Anti-Mage activates Black King Bar.
* Corrosive Haze allows allies to take down Anti-Mage before he has a chance to Blink, and maintains vision over him even if he does Blink away.
Additional:
* Slithereen Crush and Bash of the Deep deals physical damage, bypassing the magic resistance bonus from Counterspell
* Corrosize Haze significantly increases the damage dealt against Anti-Mage, and makes it harder for him to flee with Blink, although Anti-mage can block its casting with with Counterspell

* Firestorm's percentage damage can quickly demolish the Spirit Bear's high HP
* Pit of Malice will allow allies to easily kite Lone Druid due to his low mobility

* Underlord's Atrophy Aura reduces Morphling's high base damage gained through agility shift.

* In general, attacks of the melee 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, and will be unable to ambush Underlord and his team if Underlord chooses to use Dark Rift 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 with powerful rooting abilities will disable most of Pangolier's skills, a bonus point if it pierces spell immunity since it will also be able to stop Pangolier during his Rolling Thunder: Treant Protector, Meepo, Crystal Maiden, Dark Willow, Underlord, Naga Siren

* Heroes that reduce the damage that Marci can deal during her ultimate, like Razor, Rubick, Bane, Dragon Knight and Underlord.

* In general, melee heroes without blink mechanisms or spell immunity will have a hard time positioning against Pit of Malice: Sven, Tiny, Wraith King, Dragon Knight, Meepo, Doom, Bounty Hunter, Dark Seer, Undying, Alchemist, Legion Commander.

* Bounty Hunter and Slardar both have ultimates (Corrosive Haze and Track) that reveal Invoker through Ghost Walk.

* In general, attacks of the melee 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, and will be unable to ambush Underlord and his team if Underlord chooses to use Dark Rift 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.

* Crystal Maiden's already low armor and easily interruptible ultimate, Freezing Field can make Slardar her worst nightmare. Crystal Maiden also often builds Glimmer Cape which is revealed by Corrosive Haze.

* Slardar's Slithereen Crush allows him to stun Spectre and illusions, and Corrosive Haze prevents her from juking with Spectral Dagger.

* In general, melee heroes without blink mechanisms or spell immunity will have a hard time positioning against Pit of Malice: Sven, Tiny, Wraith King, Dragon Knight, Meepo, Doom, Bounty Hunter, Dark Seer, Undying, Alchemist, Legion Commander.

* In general, melee heroes without blink mechanisms or spell immunity will have a hard time positioning against Pit of Malice: Sven, Tiny, Wraith King, Dragon Knight, Meepo, Doom, Bounty Hunter, Dark Seer, Undying, Alchemist, Legion Commander.

* Heroes with spells that negate invisibility such as Bounty Hunter, Zeus and Slardar prevent her from saving her allies with Moonlight Shadow.

* Heroes with armor reducing abilities greatly hinder Visage's defense like Slardar and Dazzle.

* In general, heroes with long cooldowns on their abilities or ultimate will struggle against the relentless pressure provided by Dark Rift or Fiend's Gate (Requires Aghanim's Scepter): Terrorblade, Dragon Knight, Omniknight.

* Slardar can use Guardian Sprint with Blink Dagger or Shadow Blade to get close, and Slithereen Crush will stun Sniper and slow him, making him vulnerable to Slardar's teammates.
* Corrosive Haze lowers Sniper's armor and makes Sniper's Shadow Blade useless, easily killing him with a few attacks.

* Atrophy Aura reduces Terrorblade's damage significantly, even during Metamorphosis.
* Firestorm deals significant damage to Terrorblade and his illusions from a safe distance.
* Pit of Malice can keep Terrorblade and his illusions under control.
* Fiend's Gate can either bail out Underlord's team away from a bad engagement against a Terrorblade under Metamorphosis or caught Terrorblade off guard if he is not careful, and besides Reflection, Terrorblade has no other abilities to intercept Underlord nor his team when they use it to start a teamfight.
* Likewise, Fiend's Gate can be used to quickly move Underlord's team to the frontlines, to strike Terrorblade and his allies during Metamorphosis's 150 seconds of cooldown.
Additional:
* Atrophy Aura reduces Terrorblade's damage significantly, even during Metamorphosis.
* Firestorm deals significant damage to Terrorblade and his illusions from a safe distance.
* Pit of Malice can keep Terrorblade and his illusions under control.
* Fiend's Gate can either bail out Underlord's team away from a bad engagement against a Terrorblade under Metamorphosis or caught Terrorblade off guard if he is not careful, and besides Reflection, Terrorblade has no other abilities to intercept Underlord nor his team when they use it to start a teamfight.
* Likewise, Fiend's Gate can be used to quickly move Underlord's team to the frontlines, to strike Terrorblade and his allies during Metamorphosis's 150 seconds of cooldown.

* Damage reduction from Atrophy Aura prevents Bloodseeker from killing targets and gaining his Thirst bonuses.
* Pit of Malice's area of effect catches Bloodseeker easily, negating his speed bonus during teamfights.
* Dark Rift allows Underlord to transport Ruptured allies to the fountain, rendering it useless.

* Corrosive Haze will reveal Treant Protector even when he is under the effects of Nature's Guise.

* Heroes who can stun multiple units at once: Dark Willow, Spirit Breaker, Slardar, Invoker, and Tidehunter.

* In general, melee heroes without blink mechanisms or spell immunity will have a hard time positioning against Pit of Malice: Sven, Tiny, Wraith King, Dragon Knight, Meepo, Doom, Bounty Hunter, Dark Seer, Undying, Alchemist, Legion Commander.

* Other heroes who has armor and slow debuffs won't allow Medusa to disengage from combat: Tidehunter, Bristleback, Slardar.

* In general, melee heroes without blink mechanisms or spell immunity will have a hard time positioning against Pit of Malice: Sven, Tiny, Wraith King, Dragon Knight, Meepo, Doom, Bounty Hunter, Dark Seer, Undying, Alchemist, Legion Commander.

* 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.

* In general, attacks of the melee 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, and will be unable to ambush Underlord and his team if Underlord chooses to use Dark Rift 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.

* In general, attacks of the melee 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, and will be unable to ambush Underlord and his team if Underlord chooses to use Dark Rift 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 with high physical damage can damage Lifestealer more than he can heal: Bristleback, Clinkz, Luna,Shadow Fiend, Slardar, Terrorblade

* Slardar is one of the few meele heroes who can lane against Ursa in the early game, out harassing him with Bash of the Deep, and running away from a bad engagement with Guardian Sprint
* Corrosize Haze can force Ursa to cast Enrage defensively instead of offensively
* With Corrosize Haze, Slardar's team can quickly dispatch of Roshan, denying one of Ursa's greatest advantages