Nen, meaning "feeling" or "sense", is a core aspect of Togashi's Hunter x Hunter. It can loosely be defined as an aura that exists within most living entities, expressing their vital energies as a wide range of abilities and techniques.

RELATED: 5 Hunter x Hunter Villains ATLA's Aang Could Defeat (& 5 He’d Lose To)

Considering how risky Nen-usage can be, its existence is kept under wraps by the Hunter Association—Gon and Killua don't know about it until they pass their first exam. More importantly, there are a few Nen abilities that are dangerous even to those well-versed in the art form, due to their uniqueness, versatility, or simply because of how overpowering they are. Minor manga spoilers below.

Dragon Head — Zeno Zoldyck

Zeno Zoldyck using Dragon Lance in HxH

Zeno Zoldyck is an impossibly difficult opponent to face in battle, given that the rules rarely apply to him. . His secret weapon is Dragon Head, a technique that allows him to convert Nen into the shape of a dragon that he uses in a variety of ways.

Zeno's Dragon Dive is particularly formidable—he can break his enormous aura into thousands of tiny shards and cast them at his target, with each piece causing enormous damage upon landing.

Perfect Plan — Meleoron

Meleoron using God's Accomplice on Gon in HxH

Meleoron's Perfect Plan, also referred to as God's Alibi, is quite powerful (even if he has little to no fighting ability to speak of). This ability lets him turn invisible and intangible in every possible respect, which means that his body imperceptible to discovery.

Not even En can identify Meleoron's presence when Perfect Plan is active. He can also transfer it to others using God's Accomplice, although the loss of physical contact will void the effects in this case.

Texture Surprise — Hisoka

Hisoka using texture surprise — Hunter x Hunter

Hisoka's iconic Bungee Gum is a force to be reckoned with, but his Texture Surprise is why he's such a slippery opponent. This Conjuration-based technique can be used to imprint a variety of designs on two-dimensional surfaces.

RELATED: 10 Most Powerful Signature Moves In Anime, Ranked

In one case, Hisoka manages to temporarily quell Chrollo Lucilfer's suspicions about his motives by rewriting a prophetic declaration into an ambiguous horoscope. Texture Surprise is an incredible tool when it comes to deceiving others, something Hisoka is eerily natural at.

Crazy Slots — Kite

Kite activating Crazy Slots — Hunter x Hunter

Kite's solemn demeanor conceals the hilarious quirkiness of his Crazy Slots, an ability that is overly risky to use in general (to himself as much as his opponents). This is because it works through a roulette-based system, and the wielder himself doesn't know which weapon will emerge when he triggers Crazy Slots.

More importantly, Ging mentions that Kite can prompt a "special number" in perilous scenarios, implying that the latter's reincarnation is somehow related to his Nen.

Lovely Ghostwriter — Neon Nostrade

Neon Nostrade's Lovely Ghostwriter — Hunter x Hunter

Neon Nostrade is the keystone to her father's underworld prestige, all thanks to her Lovely Ghostwriter. Although she requires a person's name, blood group, and birthday to divine their destiny, her final product is never inaccurate.

However, it's a bit of a hassle to analyze her predictions because they appear as poetry riddled with metaphors and symbols. Nostrade's Nen ability isn't useful for combat, but she could easily topple empires with Lovely Ghostwriter.

Photon — Meruem

Meruem activating Photon and glowing — Hunter x Hunter

Meruem's aura is virtually inexhaustible to start with, and exponentially increases when he consumes and assimilates the bodies of his Royal Guards. His resurrection grants him access to Pouf's Spiritual Message, which he further modifies into Photon.

RELATED: 10 Most Powerful Characters In Jujutsu Kaisen, Ranked

This Nen technique fragments Meruem's spiritual energy into photonic particles that can be spread over a vast area near-instantaneously. Bolstered by his strength and battle prowess, Photon turns Meruem from a nation-level hazard to a world-ending supervillain.

Parallel Future — Tserriednich Hui Guo Rou

Tserriednich Hui Guo Rou's Parallel Future in HxH

A royal prince of the Hui Guo Rou family, Tserriednich's talents lie more on the diplomatic side than with Nen, but his Parallel Future is utterly terrifying nevertheless.

It is a very strange ability that few others can comprehend, but it basically involves him simultaneously perceiving the present and the future—albeit only ten seconds of the latter. Tserriednich's Nen specialty is not something to be taken lightly since he can foresee and instantly react to events before they happen.

100-Type Guanyin Bodhisattva — Isaac Netero

Netero fighting Meruem with a Buddha in the background in HXH

Netero's Nen has been honed for several decades, ultimately resulting in a technique that can neither be dodged nor blocked. Netero's 100-Type Guanyin Bodhisattva exerts a massive force with each swing; opponents as strong as Neferpitou barely have the strength to counter a single arm.

The devastating potential of the old man's Nen ability can be seen during the short but fiery fight scene with the Ant King. In fact, Meruem is shocked to learn that there are humans as overwhelming as the Hunter Association chairman, offering his respect at multiple points over the course of their deathmatch.

Skill Hunter — Chrollo Lucilfer

Chrollo Lucilfer holding Bandit's Secret in HxH

Chrollo's Skill Hunter is very similar to All For One's Quirk in My Hero Academia in that both characters can steal Nen abilities belonging to others (and do so without compunction).

RELATED: Most Powerful Monsters In Goblin Slayer, Ranked

While Chrollo may not be as obnoxious as AFO, he isn't any less dangerous. The Phantom Troupe leader stores the stolen abilities within Bandit's Secret, a book that can be conjured whenever he needs to use a particular Nen technique. What's scarier is that Chrollo knows exactly how to bypass the many drawbacks of Skill Hunter.

Wish Granting — Alluka/Nanika

Nanika manifesting in Alluka's body in HxH.

Alluka is "possessed" by an unknown being from the Dark Continent, known as Nanika to the Zoldyck family. It is capable of granting wishes, no matter how impossible they might seem. Silva, Kikyo, Illumi, and Milluki believe that the entity is extremely dangerous, but Killua realizes that it is as innocent and naive as his baby sister.

Despite Nanika's childlike behavior, its Nen is by far the most powerful in the story, not to mention one of the most unreliable—a combination that is an apocalypse waiting to happen.

NEXT: 10 Most Heartfelt Friendships In Hunter X Hunter