The power of Nen in Hunter x Hunter is as diverse as it is complicated—both for characters to employ and for audiences to comprehend. There are six natural divisions of Aura, namely, Emission, Transmutation, Manipulation, Conjuration, Enhancement, and Specialization, based on which each Nen-user constructs their personal techniques.
However, the ability itself is based on Hatsu, which gives tangible expression to a person's aura. A few well-known examples include Killua's Lightning Palm, Biscuit's Magical Esthetician, and Kortopi's Gallery Fake. While several Nen abilities are quite overwhelming, some fail to impress in more ways than one.
10 Knuckle's Hakoware Is Too Complicated To Use In Battle
Knuckle Bine's Hakoware is a technique that involves a cuddly creature known as Potclean, or Amortizing Power Redirector, which basically transports any damage received back to the enemy (except in terms of "aura interest.")
While this is quite efficient against Gon, who is ultimately defeated by the intricate math involved, it doesn't do much against opponents like Menthuthuyoupi, who possess incalculable reserves of Nen aura. Hakoware's basic idea is simple enough, and though Knuckle understands how it works, there is a small probability that the outcome will be drastically different.
9 Sadaso's Aura Arm Is Useless Against Strong Opponents
Sadaso, one of the Heavens Arena combatants, uses something known as Aura Arm— his transmutation technique converts energy into an imperceptible and gigantic limb, which he can then control as an extension of his body.
His Zetsu is sharp enough to prevent Zushi from sensing his intentions before the latter is kidnapped, Aura Arm is ineffective on experienced opponents. In fact, Killua successfully intimidates Sadaso into leaving Heavens Arena and Yorknew City forever.
8 Pokkle's Rainbow Arrows Are Strong, But Lack Strength
Pokkle graduates from the 287th Hunter Exam along with Gon, Hisoka, and the others, but Master Wing mentions at one point that he finds controlling his Ren a difficult task. As this is core to mastering Nen, it shows in Pokkle's mediocre technique: Rainbow Arrows.
Being an archer, Pokkle naturally gravitates towards the bow and arrow and therefore uses his Emission to develop the Seven Spectrum Array, each arrow being used for something unique. For example, his Orange Arrow is superfast, while his Red works like an incendiary bomb. None of this can prevent Pokkle's capture and subsequent murder by the Chimera Ants.
7 Gido's Tops Are One-Trick Ponies
Gido has obtained a range of techniques during his stint at Heaven's Arena, but all of them have to do with his Dancing Tops.
His Battle Waltz has very few blind spots, but Gon observes that his props aren't following a specific pattern and are, interestingly, random in their movements. Regardless, his Tornado Top might be quite effective, but they fail to impact Gon the second time he fights Gido.
6 Welfin's Missileman Can Go Very Wrong Very Quickly
Welfin, one of the surviving Chimera Ants, manifests his Nen Conjuration skillset into Missileman, except the issue he faces is that he rarely gets the opportunity to trigger his ability—which suggests a lack of experience.
This makes it more complicated for Welfin because Missileman requires three stages to be checked off first—identifying an opponent, attaching a command or a query to his projectile, and waiting for his enemy to react accordingly. Unfortunately, the technique can backfire for several reasons, such as inaccurate targeting or indomitable opponents.
5 Basho's Great Haiku Is Limited In Several Ways
Basho is one of the Hunters working with Kurapika when hired to protect Neon Nostrade, revealing that his Nen ability is called Great Haiku during the application exam. It allows him to bring out anything he jots down, whether it's a task or an event, as long as it's in flawless haiku form.
However, the outcome relies mainly on how good the haiku is, with poor poetry presumably resulting in weaker effects. Also, it takes time for anyone to perform the physical act of writing, which is rarely available in the midst of combat.
4 Binolt's Scissor Hands Can Only Be Used So Many Times
The Serial Killer Binolt appears as a minor antagonist in the Greed Island Arc. He is a lot more powerful than either Killua or Gon, but not Biscuit, which is why the latter forces him to train her new students under threat of death.
His Scissor Hands: Demon Barber technique involves Binolt chopping and consuming his opponent's hair, from which he derives his opponent's body stats. What difference is this going to make if all he can do is realize how hopelessly outmatched he is?
3 Riehlvelt's Aura Burst Is Two-Dimensional At Best
Riehlvelt is clearly one of the stronger Nen-users in the world, relying on his iconic bullwhip abilities like Thunder Snake and Song of Defense. Neither of these moves employs his life energy but are still capable of taking Riehlvelt all the way to Heavens Arena's prestigious 200th floor.
His actual Nen technique, Aura Burst, allows his wheelchair to move extremely fast, thereby evading or dodging oncoming attacks. The problem, as Riehlvelt learns to his displeasure, is that he can only escape his opponents in two dimensions, leaving himself open from above (and, presumably, below.)
2 Leol's Rental Pod Requires Too Many Conditions
After Pouf's intervention, Leon draws from the Specialization category to create his Rental Pod—a small music-player device that stores "borrowed" Nen techniques from his opponents (as well as allies.) He can access any of them by simply scrolling through the list and selecting the most appropriate one for the situation.
Rental Pod has two major conditions that double as drawbacks: Leol should have observed or at least learn what the technique is called, and he needs to perform a "favor" for the target and obtain the latter's gratitude verbally.
1 Kurapika's Chain Jail & Judgement Chain Can ONLY Be Used On The Phantom Troupe
Kurapika comes up with several fascinating Nen abilities, such as Dowsing Chain, Holy Chain, Steal Chain, Stealth Dolphin, and, most importantly, his nigh-invincible Specialist technique, Emperor Time.
However, to receive enough power to carry out his revenge, Kurapika makes a Nen vow that using either Chain Jail or Judgement Chain against anyone other than the Phantom Troupe (or himself) would instantly cause his heart to explode. These techniques are especially impractical because they are so heavily restricted.