* Decay can be good against Centaur Warrunner, as reducing the health of Centaur can make Double Edge risky.
* His zombies do not proc Retaliate, as it only procs for regular attacks.

* Decay, Soul Rip and Flesh Golem all deal magical damage which ignores Bulwark.
* Decay reduces Mars' natural strength and therefore his health pool, which is what he relies on to trade effectively in lane.

* Rage, acting as a pseudo-Black King Bar, completely negates Mars' initiation if used in time.
* Feast does damage and heals based on max health, perfect against high-health strength heroes like Mars.
* Infest allows Lifestealer to potentially save allies from Mars' initiation with a quick burst of extra health.

* Feast is an effective tool against Centaur Warrunner, who generally has high health and low armor, and compensates the reflected damage of Retaliate.
* If activated, Rage can protect Lifestealer from Hoof Stomp, Double Edge, and Stampede.

* X Marks the Spot negates Stampede.

* Kunkka's Ghostship and Torrent disrupt fights in Arena Of Blood.

* Heroes that have high health but little to no magic resistance are easy prey for Necrophos, as no matter how high they build their health up, Reaper's Scythe will kill them outright as long as they fall under a certain threshold, and Heartstopper Aura will deal the same amount of damage regardless, decaying their health the longer they stay within range. As such, Strength heroes like Chaos Knight, Centaur Warrunner or Magnus are good targets for his ultimate.

Additional:
* With high health and rarely buying Linken's Sphere or Black King Bar, Centaur Warrunner is a good target for Reaper's Scythe. However, Centaur Warrunner can resolve this problem by buying Hood of Defiance and it's upgrade Pipe of Insight to diminish its damage.
* Heartstopper Aura will do well against high health heroes such as Centaur Warrunner.

* Necrophos' largely magical damage completely ignores Bulwark.
* Ghost Shroud protects Necrophos from God's Rebuke but more importantly stops Mars from being a threat in lane.

* Burning Spear's magical damage is very troublesome for Mars in the laning stage.
* Life Break's percentage-based magical damage bypasses Bulwark, and can also be used to jump in or out of Arena Of Blood.

* Rebound allows her to jump in or out of the Arena Of Blood. She can save her allies from the Arena with Dispose as well.

* 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.

* Venomancer's poison attacks are all magical damage, ignoring Bulwark.
* Venomancer's multiple slows are especially effective against Mars' low mobility.
* Plague Wards can attack through Arena of Blood.
Additional:
* Venomancer's spells all deal magical damage, ignoring Bulwark.
* Venomancer's multiple slows are especially effective at kiting Mars.
* Plague Wards can attack through Arena Of Blood.

* Solar Guardian can save allies caught inside Arena of Blood

* Kinetic Field and Glimpse can completely negate Stampede.

* Mars' own father is a formidable foe because Zeus deals massive amounts of magical damage. The high damage, low cooldown nukes of Arc Lightning and Lightning Bolt combined with the percent health magic damage of Static Field will shred Mars' health because it bypasses Bulwark completely.

* Arcane Orb's pure damage ignores Mars' Bulwark.
* Astral Imprisonment can be used to stop Mars from being disruptive or save allies from his abilities.
* Sanity's Eclipse deals high damage to Mars, due to his low intelligence.

* Time Dilation while Spear of Mars and God's Rebuke are on cooldown will make these abilities unusable for a long time, rendering Mars nearly useless.
* Mars cannot turn inside the Chronosphere, which makes it easy to attack him from the back, bypassing Bulwark completely.
Additional:
* Time Walk allows Faceless Void to escape or enter Arena Of Blood, and helps him recover from Mars' burst damage.
* Time Lock's magical damage ignores Bulwark.
* Chronosphere allows Faceless Void to reposition behind Mars, ignoring his Bulwark while he is helplessly frozen in time.

* If Mars lanes middle, Shadow Fiend can keep the lane pushed against him.
* Shadow Fiend can go an entirely magical based build, which is very effective against Mars.

* Berserker's Call forces Mars to face in the direction choosen.
* Counter Helix is a much stronger lane trader than Spear of Mars.

* Mars has no way to trade with Ogre Magi in the early game thanks to his high base health, resistance and Ignite.
* Once Ogre Magi gets level 2 he may also have Bloodlust, which makes him even harder to deal with in lane.
* Fireblast can be ridiculously strong later on in the game for controlling Mars.
* Spear of Mars, which is Mars' main source of damage in the early game, cannot guarantee kills early on Ogre Magi.

* Centaur has nothing to deal with Refraction that will negate all of his burst damage.
* Psionic Traps provide good vision, making for him harder to initiate.

* Dragon Slave deals reliable magic damage during the laning phase against Mars.
* Lina's Eul's Scepter of Divinity and Light Strike Array combo can interrupt Mars from being disruptive for a decent amount of time and leave him vulnerable for follow up stuns.
* Laguna Blade deals massive magical damage, and pure damage with Aghanim's Scepter.

* Nethertoxin disables Bulwark entirely, making Mars far less tanky. Using Nethertoxin inside Arena of Blood may discourage enemies from following up with Mars' initiation.
* Rod of Atos is currently common on Viper and keeps Mars in position long enough to be killed.
* Beware that Viper is not very tanky earlier in the game, so positioning against Mars is important since a well-timed Spear of Mars can be the end of Viper.
Additional:
* Nethertoxin breaks the damage block from Bulwark.
* Poison Attack and Viper Strike's slows make it difficult for Mars to contribute to fights due to his low mobility.

* Storm Spirit's abilities all do magical damage, which can bypass Bulwark.
* Ball Lightning can escape through Arena of Blood and it is easy to dodge Spear of Mars.
Additional:
* Ball Lightning makes it almost impossible to catch Storm Spirit without someone else initiating for you.
* Overload is not reduced by Bulwark and the magical damage spam can wear down Mars quickly.

* Sticky Napalm slows turn rate, making it difficult for Mars to control the direction he is facing to activate Bulwark.
* Flaming Lasso disables Mars while enemies re-position themselves behind Mars to avoid Bulwark.

* Nether Blast, Decrepify and Life Drain deal high magical damage and bypasses Bulwark.
* Nether Ward reduces the amount of abilities Mars can use during fights and forces Mars to be careful about the heavy mana cost of Arena Of Blood.
* Pugna is one of few heroes that can contest Mars' ability to push and defend towers early on.

* Heroes that can save their allies can be a big problem for Mars: Dazzle, Omniknight.

* Heroes with high magical or pure damage will bypass Bulwark: Timbersaw, Dark Willow, Enigma, Invoker, Pugna, Skywrath Mage, Tinker, Zeus, Oracle.

* Ursa is a special mention because despite Bulwark diminishing most of the damage Ursa does, he is quite durable, especially with Enrage, discouraging the aggressive all-in playstyle of Mars; Ursa can simply not target Mars.

* Heroes with high magical or pure damage will bypass Bulwark: Timbersaw, Dark Willow, Enigma, Invoker, Pugna, Skywrath Mage, Tinker, Zeus, Oracle.

* Heroes with high magical or pure damage will bypass Bulwark: Timbersaw, Dark Willow, Enigma, Invoker, Pugna, Skywrath Mage, Tinker, Zeus, Oracle.

* Heroes that can save their allies can be a big problem for Mars: Dazzle, Omniknight.

* Heroes with high magical or pure damage will bypass Bulwark: Timbersaw, Dark Willow, Enigma, Invoker, Pugna, Skywrath Mage, Tinker, Zeus, Oracle.

* Heroes with long cast animations can be continuously interrupted by Battery Assault: Centaur Warrunner, Jakiro, Leshrac, Naga Siren, Underlord.

Additional:
* Battery Assault easily interrupts Centaur Warrunner due to his poor cast animation.
* Power Cogs can negate Stampede.

* Winter Wyvern's Arctic Burn can also be a useful tool against Centaur, who generally has very high health. Winter's Curse on Centaur can cause Retaliate to damage allies who are forced to attack him.

* Heroes with high health especially Strength heroes will take more damage on Sun Ray: Axe, Pudge, Bristleback, Mars.

* Heroes that depend on disrupting fights with ability combos or big ultimate abilities are vulnerable to the long stun of Fiend's Grip: Disruptor, Death Prophet, Enigma, Faceless Void, Invoker, Lich, Magnus, Mars, Medusa, Outworld Destroyer, Phoenix, Puck, Queen of Pain, Shadow Fiend, Treant Protector, Underlord, Winter Wyvern, Witch Doctor, Zeus.

* Heroes with high magical or pure damage will bypass Bulwark: Timbersaw, Dark Willow, Enigma, Invoker, Pugna, Skywrath Mage, Tinker, Zeus, Oracle.

* Heroes with high magical or pure damage will bypass Bulwark: Timbersaw, Dark Willow, Enigma, Invoker, Pugna, Skywrath Mage, Tinker, Zeus, Oracle.

* Heroes with break abilities: Shadow Demon (with Aghanim's Scepter), Viper.

* Heroes with high magical or pure damage will bypass Bulwark: Timbersaw, Dark Willow, Enigma, Invoker, Pugna, Skywrath Mage, Tinker, Zeus, Oracle.

* Bulwark is generally irrelevant against Riki as he primarily deals bonus damage from behind.
Additional:
* Blink Strike gives bonus backstab damage. Along with Tricks of the Trade it completely bypasses Bulwark.

* Luna's Moon Glaives will not trigger Retaliate if they hit some other target first. Also Luna commonly buys items that provide lifesteal such as Satanic, which lets her heal from the damage of Retaliate, meaning that Retaliate has little effect against her.
* Eclipse can be used to counter-initiate against Centaur Warrunner after he jumps in with Blink Dagger, and initiates with Hoof Stomp. But remember that Centaur Warrunner can resolve this problem by buying Hood of Defiance and it's upgrade Pipe of Insight to diminish its damage. Or Blade Mail to reflect the damage of the Eclipse back at Luna.
* Luna also commonly buys Black King Bar, which will allow her to protect herself from both, Centaur Warrunner's abilities (except for the Retaliate), and damage reflect from Blade Mail.
Additional:
* Luna's Moon Glaives will not trigger Retaliate if they hit some other target first. Also Luna commonly buys items that provide lifesteal such as Satanic, which lets her heal from the damage of Retaliate, meaning that Retaliate has little effect against her.
* Eclipse can be used to counter-initiate against Centaur Warrunner after he jumps in with Blink Dagger, and initiates with Hoof Stomp. But remember that Centaur Warrunner can resolve this problem by buying Hood of Defiance and it's upgrade Pipe of Insight to diminish its damage. Or Blade Mail to reflect the damage of the Eclipse back at Luna.
* Luna also commonly buys Black King Bar, which will allow her to protect herself from both, Centaur Warrunner's abilities (except for the Retaliate), and damage reflect from Blade Mail.

* Snowball can protect Tusk and his teammates from a Spear of Mars stun after an Arena of Blood, and with proper targeting, even bring them out of the Arena. This is especially noticeable in the earlier stages of the game before allies buy Black King Bar and rely on this less. Even during the late-game, Tusk can purchase a Blink Dagger to save allies that are caught before Black King Bars can be used by Blinking in and Snowballing out.
* Tag Team is a constant threat to Mars in-lane, as even with early Bulwark points it deal so much damage and slow that Mars is forced to back off from the lane and play defensively every time the spell is used.
* Worth noting is that Ice Shards can be detrimental to Tusk's own team by creating terrain that Spear of Mars can latch on, though using it conservatively is a good enough solution in most cases.