Hair Color:
White

Eye Color:
Deep teal (1999), Royal blue (2011)

Blood Type:
A

Occupation:
Assassin, Hunter

Nen Type:
Transmutation

Killua is a member of the Zoldyck family, who are all legendary assassins. Since birth, he trained endlessly in the art of assassination. He eventually ran away from his family and profession to participate in the Hunter exam. He befriended [Gon](https://anilist.co/character/30/Gon-Freecss) almost immediately and has loyally followed him since then. Killua is usually a kind-hearted and playful boy, but once provoked he becomes extremely violent and bloodthirsty. This seems to be a trait he got from [his father](https://anilist.co/character/60/Silva-Zoldyck), who believes that Killua would eventually return home as an assassin. He is also a transmuter and constantly strives to improve his nen ability, developing many interesting techniques as the show progresses.
##__Killua's Abilities__
~!__Lightning Palm__ (雷掌 Izutsushi)
Type: Transmutation
The first ability Killua named, as well as the most basic one in his arsenal, consists in him electrocuting his opponent by touching them with both palms and pushing them back. The first and only time this Nen ability was used, it barely seared [Sub](https://anilist.co/character/33304/Sub)'s sweater, but hurt and stunned him for a few seconds.
__Thunderbolt__ (落雷 Narukami)
Type: Transmutation
Killua leaps into the air above the opponent and projects a bolt of lightning from his fingers, paralyzing them for a few moments and causing them pain. Although the ability was unable to inflict any visible damage to [Rammot](https://anilist.co/character/83211/Rammot) even before the latter learned Nen, it succeeded in stunning [Menthuthuyoupi](https://anilist.co/character/43953/Menthuthuyoupi). On both occasions, Thunderbolt was utilized to allow an ally to strike the opponent while they were vulnerable.
__Godspeed__ (神速 Kanmuru)
- Whirlwind (疾風迅雷 Shippū Jinrai)
Type: Transmutation
The first core function of Godspeed has Killua react automatically to external stimuli. Instead of the normal process of the stimulus being perceived by the nerves, which transmit a signal to the brain which in turn sends an instruction to the muscles, Killua programs his aura to send an electric signal to his muscles so as to instantly react to a threat, bypassing the comparatively slow nervous system. The aura can be preprogrammed to respond to different stimuli: physical contact, malevolent intent in enemy aura, or someone stepping in a predetermined perimeter, and the specific response is preprogrammed as well.
Concretely, this results in a drastic boost to Killua's reaction time, which has both offensive and defensive uses. When Killua used a prototype of this ability, he was able to grab a dart between the instant it was conjured, already in contact with his skin, and the moment it punctured it. Whirlwind is also effective as an offensive ability. If the opponent executes the action Killua has preprogrammed a response for, he will, in most cases, be able to land an attack before they can, thanks to both his reaction and his movement speed being drastically enhanced. When he used this application of Godspeed against Menthuthuyoupi, Killua was able to momentarily disappear from his sight, and struck him several times without the latter being able to do anything, the short lapse between the Royal Guard's aura surging and him taking any action being enough for Killua to preempt any move his adversary could make. Youpi himself admitted to being completely powerless throughout the beating. On that occasion, despite his attacks inflicting no damage at all, Killua's electricity proved powerful enough to elicit screams of pain out of Youpi, as well as to paralyze him for a few instants. When he later used the same ability against [Shaiapouf](https://anilist.co/character/41135/Shaiapouf)'s clone, which is considerably swift in its own right, Killua was able to dodge its attacks with [Komugi](https://anilist.co/character/14313/Komugi) on his back, leading Pouf to fear that even with all his cells, he would have a hard time catching him, and then burn off its cells by generating an electric current between his fingers whenever it stepped into a circle he had drawn.
Since giving an order to one's aura is generally a Manipulation skill, it is possible, albeit unconfirmed, that Whirlwind makes use of this Nen category.
- Speed of Lightning (電光石火 Denkō Sekka)
Type: Transmutation
The second application of Godspeed allows Killua to retain conscious control of his movements. His running speed and jumping ability increase dramatically, hence why he uses it primarily to cover long distances in a very short amount of time. As a consequence, this core function is more affected than Whirlwind by the terrain: Tsubone was able to keep Killua in sight while he was running through the woods, but was shaken off as soon as he reached a paved road. However, even at full throttle, he was severely outsped by Tsubone's motorcycle transformation while she had two riders. The butler estimated that by crossing the woods, it would take Killua 10 minutes to reach a destination about 40km (approx. 24.8 mi.) away, whereas a car driver would take twice as long. This suggests that on unfavorable terrain, Killua's speed with Speed of Lightning is approximately 240km/h (about 149.1 mph). If he carries someone, they will suffer mild electric shocks as long as they are in contact with him.!~
(Source: Hunter x Hunter Wiki)