Hisoka's origins are mysterious and unknown, as he is the type of character that is an enigma who speaks little about his origin. However, he has stated that his family was poor when he was growing up, and he often chewed a brand of gum called Bungee Gum until it lost its flavor because of this. Sometime before the beginning of the series, Hisoka joined the Phantom Troupe, a group of infamous thieves. In the beginning of the manga, Hisoka is a serial killer who entered the 287th Hunter Exam, and ended up meeting the protagonist Gon Freecss during the exam. Hisoka became interested in Gon due to his great talent and potential to become strong, and ended up forming a sort of rivalry with Gon after telling him to get stronger before they could fight for real. While Gon was training to fight Hisoka in the Heavens Arena, he and his friend Killua found that Hisoka was fighting at the 200th floor of the arena. After training in the art of Nen, Gon battled Hisoka, though he ended up losing, but the fight made Hisoka even more interested in him.
Superhuman Physicality: Hisoka is incredibly strong, and ranked third in the Phantom Troupe in terms of strength. He is also impervious to pain, not even reacting to his limbs being severed.
Prenatural Perception: Hisoka can sense the presence of others, even if they've hidden their aura using Zetsu. He is also able to gauge a person's talent and can create a point-based system to quantify them. Because of his vast fighting experience, he can discern a person's strength by just looking at them, and can detect a very strong individual nearby and measure their strength, despite not even knowing them in the first place.
High Intellect: Hisoka is considered to be one of the most intelligent characters in the Hunter X Hunter series. He deduced Kastro's Nen ability just by letting him hit him, when even Killua couldn't figure it out. He can categorize any Nen users by their so-called 'attitude' and their behaviour.
Nen: Nen is the ability to use the life energy, or aura, of the user and manipulate it. Hisoka's Nen type is Transmuter, meaning he specializes in making his aura mimic the properties of something else.
Ten: By forming a shroud of aura around the user's body, they can use it as a basic defense against Nen attacks, though it doesn't protect against physical attacks. Ten also slows down the user's aging process and keep their body from breaking down over time.
Zetsu: Keeps the user's aura from leaking out of their body, making them harder to sense and relieving fatigue, at the cost of leaving them defenseless against Nen attacks.
Ren: Expands the size and intensity of the user's aura to boost their strength and durability.
Gyo: Focuses aura into a single part of the body to increase its strength, at the cost of leaving the rest of the body more vulnerable. Using Gyo on the eyes allows the user to see someone else's aura, or other hidden objects.
In: An advanced form of Zetsu that hides the user's aura without forcing them to shut it off, making it perfect for sneak attacks.
En: Expands the user's aura in a spherical radius around them, letting them sense the shape and movement of anything that enters it.
Shu: Extends the user's aura onto an object that they're holding, enhancing its strength.
Ko: Concentrates all of the user's aura into one part of their body, making it incredibly powerful, at the cost of the rest of the body being completely defenseless.
Ken: A combination of Ten and Ren, using Ren to enhance the user's aura before enveloping themselves with it, providing greater defense than Ten.
Ryu: The real-time use of Gyo, shifting the concentration of aura between two body parts in quick succession.
Hatsu: The unique way that a person uses their Nen ability, each of which is exclusive to the specific wielder.
Bungee Gum: Bungee Gum lets Hisoka alter his aura's consistency, making it stretchy and sticky. It can stretch and contract on Hisoka's command, stick to anything so Hisoka can pull it towards him, or vice-versa, and bounce back projectiles that hit it. By using In to hide his aura, Hisoka can turn his Bungee Gum invisible. Currently, Hisoka has an artificial arm and leg made out of Bungee Gum, which lacks the adhesive properties of it, but can still stretch and contract. By wrapping Bungee Gum around his heart and lungs, Hisoka can restart them if they stop, bringing him back from death.
Texture Surprise: Texture Surprise applies Hisoka's aura to a thin surface, changing its appearance.