Slardar/Counters

Bad against...

 * applies a basic dispel that purges.
 * is able to purge off Slardar's and  stun/slow from any allies Oracle chooses to cast it on.
 * can also be cast on Slardar to prevent him from proccing his.


 * Abaddon can cast on any of his allies to immediately purge  and/or the stun and the slow components of.
 * All of Slardar's debuffs are also removed if Abaddon's triggers.


 * Phantom Lancer has a low cooldown basic dispel from, making it hard to keep on him. Can also build  and.
 * Slardar does not do well against illusions and has a low mana pool, making Phantom Lancer with annoying, to say the least.
 * means you can't away from his illusions either, forcing you to Blink,  or get your  cancelled.


 * Slithereen Crush maybe useful for Meepo but Meepo attack more frequently with Geostrike. Some Slardar hasn't build Black King Bar, Earthbind and Poof are enough for kill him.


 * Though he has Bash of the Deep which useful for battle, but he has worse attack speed and no healing source like LC. So, Slardar will lose when dueled.

Others

 * cares less than other heroes about armor reduction, since blocks 60% of all damage without taking armor/magic resistance into consideration. This makes 60% of your  ineffective until Medusa's mana is drained.
 * 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.
 * Slardar relies on initiation, so any illusion-based hero (especially with ) can scout you out and/or cancel your blink.
 * Illusion heroes like Phantom Lancer, Luna, Arc Warden.

Items

 * Given that Slardar's damage output is entirely physical, there is almost nothing he can do when you activate.
 * provides armor which helps against Slardar, while the passive attack slow also prevents him from attacking as often.
 * ,, , can reduce the value of your  with constant misses and can be hard for Slardar to itemize against, requiring ,  or both. Also true for his allies that want to take advantage of the armor reduction.
 * and can be a pain to deal with until Slardar gets a.

Good against...

 * Invisible and fragile. With Diffusal Blade no longer capable of dispelling Corrosive Haze Riki lacks a good option against Slardar: Riki will not win most straight-up fights even without being stunned, and doesn't have nearly enough health or armor to survive being focused on with Corrosive Haze.  Slardar's Guardian Sprint is usually enough to chase effectively, and even Riki's ultimate will rarely deal enough damage to matter much against Slardar.  If you find yourself in this untenable position it is recommended to use Blinding Cloud aggressively or have a support interfere with Slardar.


 * Clinkz is fragile and relies on invisibility. Amplifying the damage Clinkz takes leaves him extremely vulnerable. Meanwhile, Slthereen Crush can pin Clinkz down long enough to kill him with even modest support.


 * Like Clinkz, Bounty Hunter's escape method is countered effectively by Corrosive Haze. Track can help Bounty Hunter escape, but Guardian Sprint provides more than enough speed to chase even with this benefit.


 * Glass cannon, invisible escape.


 * Glass cannon, a usual shadowblade builder

Others

 * Invoker's Ghost Walk can be countered, though he can counter with other escapes like Tornado.
 * Nyx Assassin's Vendetta can be revealed, and Corrosive Haze's short cooldown is ideal for breaking Linken's Sphere.
 * Slark's Pounce can be interrupted with Slithereen's Crush because few Slark build Black King Bar to fight him. But if that Slark is smart enough to purge Corrosive Haze. You must buy mobility item like Silver Edge or attack item like Echo Sabre, Monkey King Bar to double bash him.
 * Crystal Maiden
 * Mirana
 * Linken's Sphere heroes because Corrosive Haze has shorter cooldown than Spellblock 8 seconds (13-5).
 * Slardar's Bash of the Deep is Physical so Black King Bar won't prevent this.
 * Anti-Mage since he can't bash like Slardar.
 * Spectre
 * Bristleback for decreasing armor.
 * Broodmother for reveals under Spider Web.

Works well with...

 * Corrosive Haze significantly increases the damage from Jinada.


 * Double armor reduction leads to the enemy having little to no armor in lane.


 * Presence of Dark Lord further reduces the armor.


 * Combined with Alchemist's further armor reduction with acid spray and given the fact that his unstable concoction deals physical damage


 * Slardar makes a great infest taxi for Lifestealer which in synergy with Lifestealer's slows and Slardar's lock down and armor reduction any hero is a dead one by this infest bomb

Others

 * Elder Titan bringing enemy base armor to 0 which always forces the enemy to have minus armor
 * Phantom Assassin with the heavy physical damage given by her critical is insane in combination with Slardar
 * Anti-mage's mana break deals physical damage so in conjuction with Slardar's armor reduction everyone becomes squishy for Anti-mage
 * Basically any heavy-physical damage right-clicker for instance Chaos Knight, Sven, Juggernaut, Drow Ranger, Morphling, Ursa and so on
 * Templar Assassin and Weaver given they're both physical damage carries and have armor reduction spells as well as desolator being a core item on both

List of heroes that counter Slardar, and list of heroes that work well with Slardar.