* Mana Drain is a headache for Bristleback to deal with during the laning stage, as it denies him the ability to get last hits with Quill Spray.
* Finger of Death deals high damage to Bristleback, and only triggers his passive once.

* Duel makes Bristleback fight Legion Commander face to face, forcing him to take full damage.
* Press the Attack dispels the slow from stacks of Viscous Nasal Goo.
Additional:
* When dueled, Bristleback will have to face Legion head on, not allowing his passive Bristleback to come into effect.

* Searing Arrows and Clinkz physical damage items is almost suicidal when used on Legion Commander, as it invites an instant Duel and Legion Commander herself is a natural Blade Mail carrier.
* Duel locks down Clinkz for a long duration, preventing him from escaping with Skeleton Walk.

* Hex and Earth Spike can hold Clinkz down, giving him no chance to use Black King Bar or Skeleton Walk.
* Finger of Death quickly kills Clinkz due to his low health.

* Drow Ranger's low mobility and lack of defensive abilities makes her an easy gank target in the early to mid-game.
* A Dueling Drow Ranger will lose her precious Marksmanship, reduce her damage output significantly and will more likely lose that Duel.

* Drow has a very low health pool, allowing Lion to burst her down.
* Drow has no innate escape mechanism, making her an easy target for Lion's disables.
* Lion should be wary of Drow's Gust however, as he has no natural means to deal with it.

* Duel's long duration prevents Terrorblade from swapping his health with Sunder.
* Overwhelming Odds deals high damage to Terrorblade's illusions.

* One of Lion's level 20 talents lets Mana Drain affect 2 secondary targets. This can make things difficult for heroes like Phantom Lancer, Chaos Knight, and Terrorblade who rely on illusion armies.
* Mana Drain and Hex instantly kill any illusions. Finger of Death upgraded with Aghanim's Scepter also shreds most illusions.
* One of Lion's level 20 talents lets Mana Drain affect 2 secondary targets. This can make things difficult for heroes like Phantom Lancer, Chaos Knight, and Terrorblade who rely on illusion armies.

* High priority targets like Queen of Pain, Drow Ranger and even Anti-Mage can't get caught out from Lion's long range disables.

* Duels prevents Queen of Pain from using Blink, which may force her to purchase a Linken's Sphere
* Because Queen of Pain is also not a right-click hero, Legion won't have much difficulties in duels.
* Press the Attack dispels Shadow Strike's debuff.

* Viper's frailty and low mobility makes him an enticing Duel target and Corrosive Skin doesn't protect him against Legion Commander physical attacks.
* Press the Attack can dispel Poison Attack.
* Viper slows can easily negate by Overwhelming Odds movement speed.

* Heroes that can drain mana negatively affect Viper's ability to use Poison Attack, Nethertoxin and Viper Strike: Lion, Anti-Mage

* Special mention to Legion Commander, as she can lock down Void Spirit for a long amount of time without worrying too much about being killed by him during the Duel.

* Lion's instant cast point shuts down his initiation and buys time for his allies to catch up.
* Void Spirit has to be cautious when fighting,as he has no protection against Finger of Death.If caught out in a stun,the high magic damage could end him quickly.

* Heroes that can kill Death Prophet with nukes can prevent her from using Exorcism to its full duration or using it at all: Lina, Lion, Puck, Morphling.

* Duel is a great initiation to kill Death Prophet before she can cast Exorcism. Furthermore, Legion Commander often builds Blade Mail and can reflect Exorcism's damage to kill Death Prophet easily.

* Although Weaver can potentially Time Lapse out of any burst, Weaver has a fragile health pool, and Lion's disables can kill him before.
* Weaver is very mana dependent and has a rather small mana pool in the beginning of the game. Mana Drain can deplete him of mana and lessen his early game presence.
* Earth Spike can be point targeted and hits through Shukuchi to make him vulnerable.
* Linken's Sphere is easily broken by targeted spells with low cooldown.

* Silences and other types of lockdown that prevent Weaver from using his spells: Silencer, Riki, Lion, Legion Commander, Shadow Shaman, Bane.

Additional:
* Duel's long duration prevents Weaver from activating Time Lapse or escaping with Shukuchi.

* Lion's disables are also really effective against channeling Heroes, like Enigma or Crystal Maiden.

* Duel is a great initiation to target Crystal Maiden with, as it prevents her from using Freezing Field or any other abilities and allowing the enemy team to quickly kill her before she can aid her team in a fight.

* Overwhelming Odds deals high damage to Phantom Lancer's illusions.
* Duel's long duration prevents Phantom Lancer from using Doppelganger.

* One of Lion's level 20 talents lets Mana Drain affect 2 secondary targets. This can make things difficult for heroes like Phantom Lancer, Chaos Knight, and Terrorblade who rely on illusion armies.
* Mana Drain and Hex instantly kill any illusions. Finger of Death upgraded with Aghanim's Scepter also shreds most illusions.
* One of Lion's level 20 talents lets Mana Drain affect 2 secondary targets. This can make things difficult for heroes like Phantom Lancer, Chaos Knight, and Terrorblade who rely on illusion armies.

* Heroes with abilities or items that can silence or disable Anti-Mage for long periods of time will prevent him from Blinking away: Lion, Silencer, Shadow Shaman, Grimstroke, Witch Doctor, Riki, Faceless Void, Skywrath Mage, Puck.

* Duel renders Anti-Mage's escape capabilities with Blink and Counterspell useless. Blade Mail and Moment of Courage work well against Anti-Mage's relatively low health.
* A good initiation from Legion Commander and her team is enough to effortlessly kill Anti-Mage.
Additional:
* Counterspell offer no protection against Duel at all.
* Duel locks down Anti-Mage for a long duration, preventing him from escaping with Blink. One successful Duel initiation is usually enough for Legion Commander's team to kill Anti-Mage.

* Heroes with low health will die easily during Duels, and can be farmed for damage in the early game: Crystal Maiden, Lich, Techies, Rubick

* Heroes with forced movement abilities or non-interrupting forced movement, such as Lion, Drow Ranger, Magnus, Mars, as they can cancel blast-off mid air, removing his ability to initiate or escape.

* One of Lion's level 20 talents lets Mana Drain affect 2 secondary targets. This can make things difficult for heroes like Phantom Lancer, Chaos Knight, and Terrorblade who rely on illusion armies.
* Mana Drain and Hex instantly kill any illusions. Finger of Death upgraded with Aghanim's Scepter also shreds most illusions.
* One of Lion's level 20 talents lets Mana Drain affect 2 secondary targets. This can make things difficult for heroes like Phantom Lancer, Chaos Knight, and Terrorblade who rely on illusion armies.

* Heroes with strong area damage to destroy Phantasm illusions: Axe, Ember Spirit, Legion Commander, Phoenix

* Finger of Death can instantly shred many targets especially fragile Heroes like Keeper of the Light, Ancient Apparition, or Bounty Hunter.

* Legion Commander with Press the Attack
* Heroes that can remove the Track debuff with their skills:
* Abaddon with Aphotic Shield and Borrowed Time
* Huskar with Life Break
* Juggernaut with Blade Fury
* Legion Commander with Press the Attack
* Lifestealer with Rage and Infest
* Naga Siren with Mirror Image
* Omniknight with Heavenly Grace
* Oracle with Fortune's End and False Promise
* Phantom Lancer with Doppelganger
* Slark with Dark Pact
* Ursa with Enrage
* Weaver with Time Lapse
* Tidehunter with Kraken Shell when damage received reaches the threshold.

* Heroes with high magical burst can easily kill Huskar when he is at low health: Lion, Lina, Skywrath Mage

* Carries that can out damage Huskar will do well against him: Legion Commander, Faceless Void, Troll Warlord, Phantom Assassin.

Additional:
* Life Break is almost suicidal when used on Legion Commander, as it invites an instant Duel and Legion Commander herself is a natural Blade Mail carrier.
* Huskar's low survivability and mostly on low health makes him particularly vulnerable to Legion Commander's high physical damage.

* Enchantress is very fragile without any form of magic resistance, allowing Lion to easily burst her down.
* Nature's Attendants is a slow heal, making it ineffective against Lion's burst.
* Enchantress lacks any escape mechanism apart from her raw movement speed, allowing Lion to disable her.
* Since Lion's damage comes mostly from his skills, Untouchable does nothing to mitigate it.

* Hex greatly reduces Timbersaw's mobility.
* In addition, Lion can follow up with his Earth Spike and Mana Drain combo, preventing Timbersaw to escape with Timber Chain. And he can finish Timbersaw off with Finger of Death if the latter's HP is low enough.

* Despite her high mobility, Hex or Earth Spike can lock Phantom Assassin down and make her vulnerable.
* Although she has high evasion through Blur, Phantom Assassin has a rather low health pool, making her weak to Lion's magical burst.

* Press the Attack can dispel Blinding Light or Solar Bind from a hero.
* Duel can be used to instantly take Keeper of the Light out of a team-fight.

* Mana Drain is very effective against heroes that have mana burn abilities such as Anti-Mage, Nyx Assassin and Keeper of the Light.

* Mana Drain depletes Nercophos's mana pool, preventing him from using his abilities.
* Finger of Death deals high magical damage, which becomes amplified by Ghost Shroud.

* Mana Drain rapidly saps Morphling's already low mana pool, making him unable to use Waveform or Adaptive Strike. Additionally, Hex prevents these abilities as well.
* An Earth Spike and Finger of Death combo can burst an unwary Morphling down if he has his strength fully shifted to agility.

* Ember lacks any protection against Lion's disables early in the game and often does not acquire any later, allowing Lion to Hex or Earth Spike him before he escapes through his Fire Remnant.
* Although Flame Guard can prevent magic damage, it does not stop Lion's disables, and Lion can usually break through it with Finger of Death.
Additional:
* Lion possesses two strong disables in Earth Spike and Hex and heavy magic burst with Finger of Death which help lock him down and prevent him from escaping with Activate Fire Remnant. When getting his Blink Dagger Lion can punish Ember Spirit's overextension immediately, or initiate a fight on him with disables.

* Hex and Mana Drain can be used to immediately destroy Spectre's illusion when she Haunts. A fast fingered Lion can protect himself and a teammate.
* Hex and Earth Spike are good lockdown spells to control and kill Spectre, especially if she doesn't buy defensive items like Linken's Sphere and Black King Bar.
* Finger of Death can be used to burst down Spectre when she is low on life as she has very poor magic resistance.

* Legion Commander can use Press the Attack on an ally to dispel Dismember. The bonus health regeneration also partially counters the damage of Rot
* Duel can be used on Pudge whilst Rot is active, disabling toggling which may result in a lethal health drain that leaves Legion Commander with a successful duel.

* Sniper's low mobility and lack of defensive abilities makes him an easy gank target for the entire game, especially if Blink Dagger is picked up.

* Press the Attack dispels Venomous Gale and Poison Sting from Legion Commander or her teammates.
* Venomancer is an ideal target for Duel due to his lack of mobility and low starting health.

* Duel pierces spell immunity and forces him to attack Legion Commander, making him unable to use Omnislash.

* With a lot of disables with good range, he might cancel your Echo Stomp.
* Mana Drain can be used to drain Elder Titan's already low mana pool.

* Chen's fragility and low mobility make him an enticing Duel target.
* Overwhelming Odds and Moment of Courage can take advantage of converted creeps' numbers.
* With enough damage from Duel stacks, Legion Commander can also often kill any of Chen's unfortunate allies before he can use Hand of God.
Additional:
* Chen's frailty and low mobility make him an enticing Duel target.
* Overwhelming Odds and Moment of Courage can take advantage of converted creeps' numbers.
* With enough damage from Duel stacks, Legion Commander can also often kill any of Chen's unfortunate allies before he can use Hand of God.

* Hex's instant cast time will force Brewmaster into the awkward situation of needing some form of spell immunity or block to prevent being immediately hex upon blinking in, or wait until Lion has used all his crowd control before entering a fight. His direct magic burst also makes Brewmaster's Drunken Brawler worthless versus Lion.

* Overwhelming Odds's damage stacks with each enemy unit in its radius. If this hits Broodmother and a large number of spiders it can deal significant amounts of damage.
* Moment of Courage has a high chance to proc if Broodmother and all of her spiders are attacking her.
* Duel can keep Broodmother in place long enough for Legion's team to kill her.
Additional:
* Overwhelming Odds is great at killing many stacked up spiderlings, thus giving Legion Commander a large buff.
* Duel is a reliable way to lock down Broodmother, preventing her from running into the treeline.

* All of Lion's abilities are active making Demonic Purge break from Aghanim's Scepter useless.
* Hex and Mana Drain can make quick work of whatever illusions you're creating, especially when he acquires his Talents at level 20 and 25.
* An attempt to save an ally using Disruption can easily become a perfect setup for a Earth Spike or Finger of Death with Aghanim's Scepter for the enemy.

* Heroes who can dispel will be able to remove remove Soul Catcher's debuff to instantly bring the health of affected heroes back to a considerable amount: Abaddon, Slark, Legion Commander, Oracle.

* Heroes rely on their debuff to control the opponent will have a hard time against Press the Attack: Venomancer, Earth Spirit, Ogre Magi

* Any heroes with stuns or silences: Death Prophet, Lion, Shadow Shaman, Skywrath Mage

* Heroes rely on their debuff to control the opponent will have a hard time against Press the Attack: Venomancer, Earth Spirit, Ogre Magi

* Since Windranger is bad against magical damage, heroes with continuous magical damage or magical nukes can blast her: Zeus, Tinker, Leshrac, Viper, Skywrath Mage, Lion, Lina, Venomancer.

* Heroes with high magical burst damage will kill Gyrocopter before he gets to do much: Lina, Lion, Zeus

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

* Mana Drain has an extremely long range and low cooldown. It can easily deplete most heroes of their entire mana pools, especially those with smaller mana pools such as Tiny or Spirit Breaker.

* Heroes that can keep Marci for a long time in one place so she can't pursue her targets, like Bane, Lion, Shadow Shaman, Invoker, Disruptor and Kunkka.

* Heroes with low health will die easily during Duels, and can be farmed for damage in the early game: Crystal Maiden, Lich, Techies, Rubick

* Duel's long duration prevents Nyx Assassin escaping from Vendetta. With Aghanim's Scepter she can also bypasses Spiked Carapace.

* Mana Drain is very effective against heroes that have mana burn abilities such as Anti-Mage, Nyx Assassin and Keeper of the Light.

* Heroes who rely on illusions will see them destroyed easily by Overwhelming Odds: Phantom Lancer, Chaos Knight, Terrorblade, Naga Siren

* Both Hex and Mana Drain destroy Naga Siren's illusions in an instant, making it hard to teamfight or push against a team with Lion. If Lion chooses the AoE effect talent for Hex or the shard for multi-target Mana Drain, it can negate her pushing potential entirely.
* Earth Spike is an AoE disable with good damage. If used well, it can help distinguish the true Naga Siren by the damage they take (illusions take more damage).

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

* Press the Attack dispels Flaming Lasso.
* Batrider is unlikely to win a Duel in any stage of the game.

* Lion can continuously Mana Drain Tiny in the early game, depleting his small mana pool for his abilities.

* Lion has two low cast point disables (Hex and Earth Spike) to control Ursa before he buys a Black King Bar.
* Hex is one of the few abilities that cannot be dispelled even with an Aghanim's Scepter upgraded Enrage.
* Lion can control Ursa's low mana pool via Mana Drain.

* Another great threat to Riki since her Duel forces him to fight from the front and expose him for the entire duration, almost always guaranteeing an easy win (unless Riki has allies helping him).
* Moment of Courage can become hard to deal with as it doesn't cease with silence.

* Legion Commander's Overwhelming Odds deals damage for every Treant it hits, which allows it to easily wipe out large waves of them.

* Wraith King has a very low mana pool and depends on it to cast Reincarnation. Mana Drain will render him useless.
* Wraith King has very low mobility, making it easy for Lion to disable and harass him.
Additional:
* While not being able to confront Wraith King by himself, Lion's Mana Drain helps in draining Wraith King's mana, preventing him from reincarnating unless he has his Aghanim's Shard.
* Lion's Earth Spike and Hex provide decent lockdown against Wraith King as well, preventing the latter from benefiting from Vampiric Spirit bonuses.

* Medusa lacks mobility or escape mechanisms. Earth Spike and Hex can neutralize her strong damage potential and allow for Lion's team to focus her down.
* In addition to easily breaking her commonly bought Linken's Sphere with its low cooldown, Mana Drain can quickly drain her Mana Shield, making her far less tanky.

* Finger of Death can instantly shred many targets especially fragile Heroes like Keeper of the Light, Ancient Apparition, or Bounty Hunter.

* Duel is very effective against Io due to its low health and armor.

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

* Pudge, Legion Commander and Axe will make the match a living hell for you, since they are known for surprise attacks from the fog and quickly killing low HP heroes. They can also interrupt your channeling, Legion being especially problematic, as she can use Press the Attack on an ally who is hexed as well.

* If Meepo ganks Lion with Poof and Earthbind, he will be an easy target for Earth Spike & AoE Hex from his level 25 talent.

* Heroes with silences and hard stuns such as Doom, Silencer, and Lion can keep Mirana from Leaping away.

* Heroes that can protect or dispel stunned allies such as Legion Commander, Outworld Destroyer, Shadow Demon and Oracle can reduce the effectiveness of Sacred Arrow.

* Lion's disables are also really effective against channeling Heroes, like Enigma or Crystal Maiden.

* Heroes that can disable or silence Silencer for a long time, such as Bane and Legion Commander, can lock down Silencer while their allies put him down.