Dark Seer
* Strong laners are usually at a disadvantage because of how well Sven can jungle. Heroes such as 
Dark Seer. 
Underlord and 
Legion Commander may find that later Sven takes care of them very quickly after some jungle farming.
Night Stalker
* 
Warcry makes it difficult to burst Sven down with both the passive (with 
Aghanim's Shard) and active component.
* Sven under the effect of 
God's Strength and his massive physical damage make Sven very dangerous to engage in the mid game.
Dark Seer
* Heroes with fast movement abilities will suffer huge damage when afflicted by Rupture: 
Spirit Breaker, 
Earth Spirit, Dark Seer.
Additional:
* 
Rupture can deal a lot of damage to either a surged Dark Seer or his allies and prevent the target from getting into position.
Night Stalker
* 
Bloodseeker's Rupture turns Night Stalker mobility against him and 
Thirst grants movement speed bonus and vision prevents Night Stalker from initiating and re-initiating.
Dark Seer
* In general, heroes who are melee with no way to fight back can be very easily poked by Monkey King to gain his Jingu Mastery stacks: Dark Seer, 
Riki, 
Rubick.
Night Stalker
* Heroes with stronger lane presence that can threaten to kill him: 
Batrider, 
Juggernaut, 
Ursa, 
Monkey King, 
Razor.
Dark Seer
* 
X Marks the Spot prevents Dark Seer or his allies from escaping with Surge.
Night Stalker
* Void's slow is useless against Lycan by activating 
Shapeshift.
* Night Stalker's single target abilities (with the exception of Void upgraded by 
Aghanim's Scepter) is not very effective against Lycan's 
Summon Wolves during the early and mid game.
Dark Seer
* 
Flame Guard makes Dark Seer not deal any damage with his skills to Ember Spirit.
Night Stalker
* 
Whirling Axes (Melee) provides a 60% miss chance, which can make the attack speed bonus from Hunter in the Night largely ineffective.
* 
Berserker's Rage together with 
Battle Trance and 
Fervor stacks gives him a high chance of rooting Night Stalker, which allows Troll Warlord to man-fight Night Stalker in any stage of the game, regardless of whether or not it's night.
* Night Stalker is not a common 
Monkey King Bar carrier to counteract this problem.
Dark Seer
* A Sniper who is somewhat competent at positioning is hardly going to be affected by any of Dark Seer's spells thanks to 
Take Aim.
* However, an illusion of Sniper made with Wall of Replica is extremely powerful, and hard to deal with.
Night Stalker
* 
Night Stalker is all about right-clicks. His nuke, 
Void is also not that threatning once you have 
Hood of Defiance, your core item.
Night Stalker
* Heroes that rely on slows to get kills: 
Lifestealer, Night Stalker, Ursa, 
Phantom Assassin, 
Terrorblade.
Night Stalker
* Heroes with stronger lane presence that can threaten to kill him: Batrider, Juggernaut, Ursa, Monkey King, Razor.
Night Stalker
* Heroes that can punish aggressive heroes, such as: 
Leshrac, 
Shadow Demon, 
Pugna, 
Death Prophet.
Night Stalker
* Heroes that can punish aggressive heroes, such as: Leshrac, Shadow Demon, Pugna, Death Prophet.
Night Stalker
* Heroes that can punish aggressive heroes, such as: Leshrac, Shadow Demon, Pugna, Death Prophet.
Night Stalker
* Heroes that are hard to gank: 
Dragon Knight, 
Mars, 
Centaur Warrunner.
Night Stalker
* Heroes that are hard to gank: Dragon Knight, Mars, Centaur Warrunner.
Night Stalker
* Heroes with stronger lane presence that can threaten to kill him: Batrider, Juggernaut, Ursa, Monkey King, Razor.
Dark Seer
* 
Fortune's End dispels Ion Shell and Surge, making any gank attempt on Dark Seer in the laning phase likely to succeed.
* 
Fate's Edict prevents all magical damage that comes from Dark Seer's abilities.
* Fortune's End dispels Ion Shell on creeps, which Dark Seer relies on to farm and zone.
Additional:
* Fortune's End can dispel 
Ion Shell, a skill that helps Dark Seer immensely in the laning phase, as well as 
Surge, a move-speed buff, effectively allowing Oracle to control Dark Seer, especially in the laning phase.
Night Stalker
* Heroes with long disables, like 
Lion, Night Stalker, or Legion Commander, can prevent Oracle from using spells or items.
Night Stalker
* Mirror Image can be effective since Night Stalker cannot withstand fighting illusions. If he's unable to tell which Naga Siren is real, he will have a hard time landing his Void. However, if Night Stalker obtains an Aghanim's Scepter, the upgraded Void will hit and may even locate the real Naga Siren in fights.
Additional:
* 
Ensnare and 
Song of the Siren prevents Night Stalker from escaping and ganking during daytime or even nighttime.
* 
Rip Tide reduces Night Stalker's armor, making him easier to focus down.
* 
Mirror Image can be effective against Night Stalker, due to his single target abilities.
Dark Seer
* Heroes that rely on illusions typically spawn very strong illusions inside Dark Seer Wall of Replica that he can use against them or their team: 
Phantom Lancer, 
Chaos Knight, 
Naga Siren, Terrorblade.
Night Stalker
* Void's slow is dispelled by 
Doppelganger or counteracted by 
Phantom Rush.
* 
Spirit Lance's and 
Diffusal Blade's slow reduces Night Stalker's mobility and helps him or his ally escape if they're inflicted by Void or Crippling Fear.
* Night Stalker has no AoE abilites to take out Phantom Lancer's illusions. Even if Night Stalker gets an Aghanim's Scepter, there will be way too many illusions for Night Stalker to handle.
Dark Seer
* Heroes that rely on illusions typically spawn very strong illusions inside Dark Seer Wall of Replica that he can use against them or their team: Phantom Lancer, Chaos Knight, Naga Siren, Terrorblade.
Additional:
* Ion Shell helps taking down illusions quickly, making it easy to identify the real Phantom Lancer.
* Surge allows Dark Seer and his teammates to run away from Phantom Lancer, who relies on his Phantom Rush to chase enemies.
Dark Seer
* Heroes with hastes: Dark Seer, 
Lycan
Night Stalker
* 
Crippling Fear prevents Keeper of the Light from using his spells to keep his team alive during team-fights.
* 
Dark Ascension is very strong against Keeper of the Light, as it allows Night Stalker to jump the backline and quickly kill the squishy Ezalor, especially when combined with the slow from Void.
Additional:
* Keeper of the Light's Aghanim's Scepter upgrade loses much of its power, due to Night Stalker being able to reduce the duration of daytime by a lot.
Dark Seer
* Dark Seer can pull together Spectre's illusions with 
Vacuum, and 
Wall of Replica creates an illusion of Spectre that deals massive damage.
Night Stalker
* Heroes that have a weak laning stage: 
Spectre, 
Nyx Assassin, 
Clockwerk, Spirit Breaker, 
Omniknight, 
Pudge.
Dark Seer
* Heroes who rely on damage over time as Spiked Carapace can block and reflect only one instance of damage: 
Jakiro, 
Viper, 
Venomancer, 
Huskar, 
Ember Spirit, Dark Seer, 
Sand King, 
Doom, 
Dawnbreaker. However, this also means they are easily stunned.
Night Stalker
* Heroes that have a weak laning stage: Spectre, Nyx Assassin, Clockwerk, Spirit Breaker, Omniknight, Pudge.
Dark Seer
* The haste provided by Dark Seer's Surge or a {Rune:Haste} renders Lich's slows ineffective.
Night Stalker
* Heroes with low health: 
Lich, 
Crystal Maiden, Lion.
Dark Seer
* Dark Seer's Vacuum and Ion Shell can clear a wave of Chen's Creeps effectively.
* Surge applies haste movement and negates the slow from 
Penitence, allowing Dark Seer to easily escape from Chen and his creeps.
* Dark Seer's full combo from Dark Seer's Vacuum, Wall of Replica and 
Normal Punch from Aghanim's Scepter can often kill Chen or any of his allies before he can save them with 
Hand of God.
Additional:
* Dark Seer's Vacuum and Ion Shell can clear a wave of Chen's Creeps effectively.
* Surge applies haste movement and negates the slow from Penitence, allowing Dark Seer to easily escape from Chen and his creeps.
* Dark Seer's full combo from Dark Seer's Vacuum, Wall of Replica and Normal Punch from Aghanim's Scepter can often kill Chen or any of his allies before he can save them with Hand of God.
Night Stalker
* The long silence of Crippling Fear at night prevents Mirana from escaping with Moonlight Shadow and Leap. She also has really low base health, so Night Stalker can usually kill her during one cast of Crippling Fear at night.
* With Dark Ascension and 
Gem of True Sight, Night Stalker can find and kill Mirana, and he is a tanky hero capable of fighting Mirana any stage of the game.
Night Stalker
* Dark Ascension also allows Night Stalker to fly over Proximity Mines without triggering them.
* Crippling Fear is effective in stopping Techies from using Blast Off and Void is effective in stopping them from running to the safety of their mines.
Night Stalker
* Crippling Fear can silence Faceless Void for a long time, preventing him from using his Time Walk and Chronosphere.
Dark Seer
* Ion Shell destroys 
Refraction's protection stacks in short time.
* Surge ignores the massive slow from 
Psionic Trap.
Dark Seer
* Dark Seer relies on Surge for most of his mobility, so he's not very vulnerable to slows, but much more to root effects and walls or pseudo-walls such as 
Disruptor's 
Kinetic Field or 
Slark's 
Pounce.
Dark Seer
* Heroes with AoE abilities will hit Slark in Shadow Dance: 
Lina, Jakiro, Underlord, Leshrac, Dark Seer, 
Earthshaker, 
Timbersaw, Crystal Maiden.
Night Stalker
* With Dark Ascension he can keep vision on Slark, disabling his 
Shadow Dance regeneration.
* Night Stalker is very fast so without the Pounce in lane, he can simply out distance him during the night.
* Slark is matched in night vision by only a few heroes, Night Stalker happens to be one of them.
Night Stalker
* Puck cannot use any of its normal means to survive should Night Stalker catch it within Crippling Fear, and goes down quickly.
Additional:
* Void is a potent nuke that is devastating to Puck's low health pool.
* Crippling Fear silence can prevent Puck from casting spells, leaving it vulnerable.
Night Stalker
* Crippling Fear is a good way to shut down and gank Invoker in the early game..
* Void deals good damage to Invoker and makes escaping harder.
* With 
Hunter in the Night and Void, Invoker can't get away from Night Stalker and won't be able to catch him with Sun Strike during the night.
Night Stalker
* Storm Spirit is absolutely helpless if caught within Night Stalker's silence range.
* Common items a Storm Spirit will build will not remove the AoE silence.
Additional:
* Crippling Fear is a silence that can last up to 8 seconds during night, rendering Storm Spirit tied limited to his items in a fight.
* Dark Ascension allows Night Stalker to initiate on Storm Spirit across the impassable terrain around the middle lane, rendering Storm vulnerable in the early game and prevent him from snowballing.
Night Stalker
* Dark Ascension reduces vision for the enemy team, which makes it more difficult for Magnus to initiate with Blink Dagger and Reverse Polarity. It is also more likely that Night Stalker will scout out Magnus with Aghanim's Scepter and a Gem of True Sight, after which he can silence Magnus with Crippling Fear.
Dark Seer
* Venomancer is a low health hero and low range hero who is easy to harass with Ion Shell on a creep in the early game.
* Venomancer depends entirely on all his slows to keep distance or chase, but since Surge ignores slows, it is nearly impossible for Venomancer to hunt or run away from Dark Seer or his surged teammates.
Night Stalker
* With Dark Ascension and Gem of True Sight, Night Stalker can easily find and kill Riki. Riki will also find it harder to kill the tanky Night Stalker than he would many other heroes.
Night Stalker
* 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.
Night Stalker
* The long silence at night prevents Clinkz from escaping with invisibility if Night Stalker can sneak up on him. He also has really low base health, so Night Stalker can usually kill him alone during one cast of Crippling Fear at night.
Night Stalker
* Crippling Fear makes it so Axe might use 
Blink Dagger right into an AoE silence in the middle of everyone.
* Void cripples Axe's already bad movement speed and attack speed.
* Hunter in the Night makes it impossible for Axe to catch up to fleeing or escape from Night Stalker during the night.
* Lastly, Dark Ascension gives full vision over Axe before he initiates, making the opponents all recognize his location immediately and allowing Night Stalker to prevent it or vocally tell his team if needed.
* Night Stalker has very high strength gain, even in the lane, so a successful Culling Blade is very unlikely.
* Axe's 
Blade Mail will likely do nothing to Night Stalker because of his high health and certain requirements for him to do the most damage to be true.
Night Stalker
* Night Stalker is one of the best heroes to find (and silence) Tinker in the trees during Dark Ascension.
Additional:
* Night Stalker can easily find Tinker in the trees during Dark Ascension.
* Void's mini-stun will stop Rearm and 
Keen Conveyance
* Crippling Fear's silence will prevent Tinker from fighting back, as Tinker relies on his spells.
Dark Seer
* 
Living Armor can be destroyed quickly with Ion Shell.
Dark Seer
* Heroes with haste can negate Enchant's slow: 
Weaver, Dark Seer, Lycan, Centaur Warrunner.
Dark Seer
* With Normal Punch from Aghanim's Scepter, Dark Seer can gain an advantage against heroes who rely on evasion as Normal Punch has true strike: Phantom Assassin, 
Windranger, 
Hoodwink.
Night Stalker
* Durable heroes can stand against Tusk during 1v1: 
Axe, Dragon Knight, Night Stalker, Centaur Warrunner, 
Wraith King and more.
Dark Seer
* 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.
Night Stalker
* Heroes with weaker mobility will struggle to keep up with Night Stalker: 
Gyrocopter, Ursa, 
Drow Ranger
Dark Seer
* Certain heroes can mess up with Pangolier's positioning and timing (especially if he intends to use Rolling Thunder during combat): 
Vengeful Spirit, 
Keeper of the Light, Huskar, Dark Seer
Night Stalker
* Heroes with low mobility that rely on spells: 
Zeus, Lina, Crystal Maiden.
Night Stalker
* Heroes with low mobility that rely on spells: Zeus, Lina, Crystal Maiden.
Night Stalker
* Heroes with low health: Lich, Crystal Maiden, Lion.
Night Stalker
* Earthshaker must be careful not to use Blink Dagger or Aghanim's Scepter upgraded 
Enchant Totem to blink into Riki's 
Smoke Screen or Night Stalker's Crippling Fear, as these field effects will instantly silence Earthshaker and prevent him from initiating.
Additional:
* 
Fissure has a short stun and creates an impassable ridge. However, Night Stalker can fly over it during Dark Ascension.
* Night Stalker can find Earthshaker, disable his Blink Dagger with Void, and then take him out with Crippling Fear.
* Earthshaker may fail his blink combo against Night Stalker's team if he is not careful, as he can blink into the silence.
Night Stalker
* Heroes that have a weak laning stage: Spectre, Nyx Assassin, Clockwerk, Spirit Breaker, Omniknight, Pudge.
Dark Seer
* With Normal Punch from Aghanim's Scepter, Dark Seer can gain an advantage against heroes who rely on evasion as Normal Punch has true strike: Phantom Assassin, Windranger, Hoodwink.
Night Stalker
* Heroes with silence such as Riki, 
Silencer, or Night Stalker prevents Skywrath Mage from using his spells.
Night Stalker
* Heroes with weaker mobility will struggle to keep up with Night Stalker: Gyrocopter, Ursa, Drow Ranger
Night Stalker
* Heroes with low mobility that rely on spells: Zeus, Lina, Crystal Maiden.
Dark Seer
* Heroes who do not have nor rely on passive abilities make Nethertoxin much less effective: 
Clinkz, Pugna, Nature's Prophet, Dark Seer, Lycan, 
Tusk
Dark Seer
* With Normal Punch from Aghanim's Scepter, Dark Seer can gain an advantage against heroes who rely on evasion as Normal Punch has true strike: Phantom Assassin, Windranger, Hoodwink.
Night Stalker
* Any heroes with silences can negate the majority of Outworld Destroyer's damage output: Death Prophet, Night Stalker, Drow Ranger, Doom .
Dark Seer
* 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.
Night Stalker
* Heroes with mobility/escape mechanisms to dodge Ancient Apparition abilites, or to easily jump on him: Riki, 
Queen of Pain, Phantom Assassin, Windranger, 
Bounty Hunter, Spirit Breaker, Night Stalker, 
Storm Spirit, Juggernaut, etc.
Dark Seer
* 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.
Dark Seer
* 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.
Night Stalker
* Heroes that have a weak laning stage: Spectre, Nyx Assassin, Clockwerk, Spirit Breaker, Omniknight, Pudge.
Dark Seer
* 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.
Dark Seer
* Heroes with escape abilities: 
Anti-Mage Dark Seer Slark Storm Spirit Windranger Weaver can kite Lifestealer due to him having no lockdown.
Night Stalker
* Night Stalker's Crippling Fear at night prevents Shadow Walk for an extended period of time and his Void will make Phase Boots useless. If Night Stalker has True Sight, he can shutdown Bounty Hunter's sneak kill.
Night Stalker
* Heroes that have a weak laning stage: Spectre, Nyx Assassin, Clockwerk, Spirit Breaker, Omniknight, Pudge.
Night Stalker
* Heroes that have long silences, such as Night Stalker and Silencer, will prevent Abaddon from saving his allies effectively and disable the active component of Borrowed Time.
Night Stalker
* Heroes with illusions and summons can manfight Night Stalker: Terrorblade, Beastmaster, Broodmother.
Dark Seer
* Dark Seer's Vacuum and Ion Shell allows him to clear a wave of Terrorblade's illusions.
* Because Terrorblade often builds items that require 
Ultimate Orb like 
Manta Style and 
Eye of Skadi, Dark Seer can create a very strong illusion of Terrorblade with Wall of Replica and Normal Punch from Aghanim's Scepter.
* If Dark Seer can use Vacuum to help teammates land their AoE abilities, Terrorblade will be quickly killed before he even gets a chance to use Sunder.
Additional:
* Dark Seer's Vacuum and Ion Shell allows him to clear a wave of Terrorblade's illusions.
* Because Terrorblade often builds items that require Ultimate Orb like Manta Style and Eye of Skadi, Dark Seer can create a very strong illusion of Terrorblade with Wall of Replica and Normal Punch from Aghanim's Scepter.
* If Dark Seer can use Vacuum to help teammates land their AoE abilities, Terrorblade will be quickly killed before he even gets a chance to use Sunder.
Dark Seer
* Dark Seer's only disable is Vacuum. Though he starts off with high armor and health, he'll eventually have a hard time dealing with high mobility heroes such as Weaver or Queen of Pain.
Night Stalker
* The long silence of Crippling Fear at night prevents Weaver from using his Shukuchi or Time Lapse.
* With Dark Ascension and Gem of True Sight, Night Stalker can easily find and probably kill Weaver.
* Hunter In the Night's attack speed bonus removes The Swarm's beetles very quickly.
Dark Seer
* Dark Seer relies on Surge for most of his mobility, so he's not very vulnerable to slows, but much more to root effects and walls or pseudo-walls such as Disruptor's Kinetic Field or Slark's Pounce.
Night Stalker
* May effortlessly get to and take down Disruptor.
* Void deals heavy single target damage and slow. Lacking innate escape mechanisms justs puts Disruptor in trouble
* Crippling Fear silences, and Disruptor is extremely dependant on abilities to work and to fend for himself.
* Hunter in the Night provides Night Stalker movement speed, attack speed and strengthens his abilities during night time, allowing him to easily catch up and obliterate Disruptor
* With 
Black King Bar, it's mostly assured to target down Disruptor.
Dark Seer
* Dark Seer's only disable is Vacuum. Though he starts off with high armor and health, he'll eventually have a hard time dealing with high mobility heroes such as Weaver or Queen of Pain.
Night Stalker
* Night Stalker has a huge, almost instant silence through Crippling Fear. The main problem is that he can get it off while Queen of Pain barely has any vision of him if he creeps up to her during Dark Ascension. She'll have to play very carefully before she gets a Black King Bar or a 
Eul's Scepter of Divinity.
Night Stalker
* 
Phoenix turns night to day, overriding Dark Ascension during 
Supernova.
Night Stalker
* Void can interrupt 
Icarus Dive.
* His Crippling Fear's silence will shutdown a spell caster Phoenix.
* However, Phoenix punishes Night Stalker with Supernova because it will turn night into day, and it has a higher priority than Dark Ascension, effectively canceling the passive bonuses Night Stalker gets from Hunter in the Night.
Night Stalker
* Night Stalker's most skills are single targeted which allows other Meepos to Poof, Earthbind and kill him.
Dark Seer
* Dark Seer can take great advantage of 
Divided We Stand by putting an Ion Shell on a clone in order to harass them effectively.
* Vacuum can take a single Meepo and disable him for Dark Seer and his teammates to take out.
Night Stalker
* Heroes with illusions and summons can manfight Night Stalker: Terrorblade, Beastmaster, Broodmother.
Dark Seer
* Ion Shell zones out Broodmother in the laning phase, and can kill her spiderlings if used on one Spiderling in a group.
* Vacuum can pull Broodmother out of the treeline.
Additional:
* Ion Shell is a very powerful weapon against Broodmother's Spiderlings and makes her laning much harder.
Night Stalker
* Heroes with illusions and summons can manfight Night Stalker: Terrorblade, Beastmaster, Broodmother.
Dark Seer
* 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.
Dark Seer
* 
Spell Steal will easily steal all abilities from Dark Seer.
Additional:
* Spell Steal can perfect from Rubick's steal all abilities from Dark Seer. Rubick's always purchase Aghanim's Scepter can two stolens abilities from Dark Seer's and waiting for seconds for second stolen abilities (example: combinated Vacuum and Wall of Replica) and many different combination.
* A good positoning from Rubick's Spell Steal waiting steal abilities from Dark Seer Wall of Replica and illusion from Wall of Replica Dark Seer's can fighting with effect from outcome steal Wall of Replica from Rubick's.
* Combinated Rubick's steal Surge and Blink Dagger is very important catch from Dark Seer's and enemies.
* Rubick's 
Telekinesis can lifted up Dark Seer or enemy heroes and throw to Wall of Replica from Rubick's steal.
Night Stalker
* Crippling Fear silences nearby heroes and cannot be dispelled, which hinders Rubick's way to retaliate when being jumped on.
* With Hunter in the Night and Dark Ascension, Night Stalker can find Rubick easily in teamfights. The two spells grants more than enough damage to hunt Rubick down without defensive items.
Night Stalker
* Phantasm gives Chaos Knight a significant advantage against single-target damage dealers: Lifestealer, Wraith King, Night Stalker, 
Troll Warlord.
Additional:
* 
Chaos Bolt can stun Night Stalker outside of Crippling Fears relatively small radius.
* 
Reality Rift is a great way to force Night Stalker to fight Chaos Knight, a hero with massive health and damage output. It also forces Night Stalker's Crippling Fear off his primary target.
* Night Stalker doesn't have a lot of ways to deal with multiple targets, which makes him vulnerable to 
Phantasm illusions unless Night Stalker buys Aghanim's Scepter.
Dark Seer
* Heroes that rely on illusions typically spawn very strong illusions inside Dark Seer Wall of Replica that he can use against them or their team: Phantom Lancer, Chaos Knight, Naga Siren, Terrorblade.
Dark Seer
* Dark Seer's strength lies in his high-mana cost skills. So 
Mana Break can be a great nuisance for him, since it can reduce his mana and prevent him from casting his spells.
* 
Mana Void can deal a lot of damage if Dark Seer spent a lot of mana on his abilities.
Night Stalker
* Crippling Fear makes Night Stalker one of the best early game gankers to shut down Anti-Mage.
* Night Stalker's low mana pool causes him to take little damage from Mana Void.
Night Stalker
* Heroes with stronger lane presence that can threaten to kill him: Batrider, Juggernaut, Ursa, Monkey King, Razor.
Dark Seer
* Dark Seer can increase the movement speed of allies with Surge, breaking Static Link.
Dark Seer
* Abilities that deal low damage with high amounts of instances are irrelevant against Pudge during Flesh Heap's active: Gyrocopter's 
Rocket Barrage and Dark Seer's Ion Shell are just a couple examples.
Night Stalker
* Heroes that have a weak laning stage: Spectre, Nyx Assassin, Clockwerk, Spirit Breaker, Omniknight, Pudge.
Additional:
* Void's mini-stun and silence from Crippling Fear will stop Pudge from using Dismember or turning off his Rot.
* Night Stalker has naturally high health, strength gain and common itemization for survivability through magic resistance, making Night Stalker a poor target for Pudge.
Night Stalker
* Heroes with stronger lane presence that can threaten to kill him: Batrider, Juggernaut, Ursa, Monkey King, Razor.
Night Stalker
* Heroes with weaker mobility will struggle to keep up with Night Stalker: Gyrocopter, Ursa, Drow Ranger
Dark Seer
* 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.
Dark Seer
* Heroes with strong area-of-effect damaging and/or disabling abilities will be able to intercept Underlord and his team when they exit from Fiend's Gate: 
Luna's Aghanim's Scepter upgraded 
Eclipse, Dawnbreaker's 
Solar Guardian, Axe's 
Berserker's Call, Mars's 
Arena of Blood, Jakiro's 
Macropyre, 
Dual Breath and 
Ice Path, Naga Siren's Song of the Siren, Razor's 
Eye of the Storm and 
Plasma Field, Lina's 
Light Strike Array, Broodmother's 
Spinner's Snare from Aghanim's Scepter, 
Elder Titan's 
Earth Splitter and 
Echo Stomp, Alchemist's 
Unstable Concoction and 
Acid Spray, Queen of Pain's 
Sonic Wave, Dark Seer's Wall of Replica and Vacuum, Venomancer's 
Noxious Plague and 
Poison Nova from Aghanim's Scepter, 
Oracle's Fortune's End and 
Rain of Destiny from Aghanim's Shard, Bloodseeker's 
Blood Rite, Enigma's 
Black Hole and 
Midnight Pulse, 
Shadow Fiend's 
Requiem of Souls, Batrider's Aghanim's Scepter upgraded 
Flaming Lasso, 
Firefly, 
Flamebreak and 
Sticky Napalm, 
Ancient Apparition's 
Ice Blast, Sand King's 
Epicenter, 
Sand Storm and 
Burrowstrike, Gyrocopter's 
Call Down, Ember Spirit's 
Sleight of Fist, Death Prophet's 
Exorcism and 
Silence, Monkey King's 
Wukong's Command, Crystal Maiden's 
Freezing Field, 
Muerta's 
The Calling, 
Medusa's 
Stone Gaze, Zeus's 
Nimbus from Aghanim's Scepter. 
Dark Willow's 
Bramble Maze, 
Pangolier's 
Swashbuckle, 
Grimstroke's 
Soulbind, 
Ink Swell and 
Stroke of Fate, Earthshaker's 
Echo Slam and Fissure, 
Puck's 
Dream Coil and 
Waning Rift, 
Winter Wyvern's 
Winter's Curse, 
Magnus's 
Reverse Polarity.
Dark Seer
* The constant dispel from Demonic Purge will make any attempt to save the victim or himself by
Surge become futile. For what it's worth, Demonic Purge will also dispel 
Ion Shell.
Night Stalker
* Heroes that can punish aggressive heroes, such as:
Leshrac, 
Shadow Demon, 
Pugna, 
Death Prophet.