Killua Zoldyck is one of the main characters of the HunterxHunter anime and manga.
The heir to the Zoldyck family, Killua decided he didn't want to be an assassin anymore, so he ran away. However he wasn't sure of what he really did want to do, so he took the Hunter Exam as a way to entertain himself. That's where he met Gon. At first he's distant and unattached, but it's hard to stick around Gon without warming up to him. He's generally fun-loving and a tease, although he doesn't seem to know when to stop, whether it's gambling or making fun of someone. He tends to be much more logical than Gon, making them a good pair.
In the AWA fics, Killua is a student at the AWA Academy and is a part of Class 2.
In the XP4 fics, Killua debuted in XP4 Heroes Coalition - Kick-Off!.
Killua has spiky silver hair, very pale skin, and blue eyes. His eyes change shape depending on the mood that he's in, narrowing and sharpening when he goes into assassination mode. Killua is fairly lean at the start of the series, due to constant physical conditioning and torture training he received when he was young. As time passes, he becomes more muscular and toned. In the Nippon Animation anime adaptation, Killua's eye color is changed to green during the OVAs. He is also often seen holding a green skateboard (turned yellow in the 2011 series).
Killua typically wears baggy clothing, with his usual attire consisting of long-sleeved and dark-colored shirts. Most of his clothes have a turtleneck. Killua wears long, baggy shorts in the manga and Madhouse animated adaptation, but Nippon Animation's character design shortened them to reach above his knees. Killua also wears blue boots, recolored brown and black in the Nippon Animation adaptation.
Initially, Killua is introduced as a character who appears similar to Gon: cheeky, cheerful, and full of mischievous ideas. However, contrasting Gon's politeness, Killua can be quite rude to others, mostly strangers and older people. He is most commonly known for having a sweet tooth; he loves everything sweet and spent almost 200 million on snacks when he was at the Heaven's Arena. His favorite snack is chocolate, specifically Chocolate Balls.
He is also one of the quickest-thinking characters and often analyzes a situation with great ease and accuracy. In spite of his young age, his way of thinking, knowledge, and pragmatism give him the attitude of an adult. He is initially very confident about his own abilities, going as far as questioning Gon's capability during the Hunter Exam, and compares his strength with other people. As time passed, Killua became humble about it; but when somebody compliments him, especially Gon, he becomes easily embarrassed.
However, his ruthlessness and aptitude in killing show the other side of him—deadly, violent, and bloodthirsty. Conflicting with Killua's predisposal to kill is his unyielding loyalty to his friends and natural kindness. He claims Gon was his first friend, and he grows progressively more attached to him as time passes. Killua often suffers immensely in his attempts to help his friends without a single complaint. He puts others before himself without being concerned about his own health or even his life.
Until recently, Killua's greatest flaw was his fear of those seemingly more powerful than him (one of whom being his elder brother, Illumi). Killua had been trained as an assassin by his brother to be extremely cautious and that he only engages in combat provided that victory is absolutely certain. This impeded him as a Hunter, as Biscuit stated more than once that victory is never certain, and that depending on the circumstances, a person has the potential to defeat a stronger opponent.
Killua especially struggles with these dueling ideologies during the latter half of the series, as he begins to encounter stronger opponents. His brother's teachings remained firmly entrenched in his mind, to a point at which Biscuit prophesied that he would one day abandon Gon because of this. Finally, he had to face Biscuit's prophecy when he encountered a Chimera Ant while Gon (who could not use Nen at the time) was not far off and had no way to defend himself. At the last moment, Killua realized that Illumi had implanted a needle in his brain way back in the first Hunter Exam. This needle was responsible for forcing Killua to retreat and jailing himself in his comfort zone whenever any situation would potentially endanger his life. Upon extracting the needle, Killua was freed from this restraint and gained full control of his subconscious to make his own decision whether or not to flee whenever there is a need to fight stronger opponents.
During the events of Greed Island, Killua has shown to be highly susceptible to gambling. Going as far to be willing to gamble with his life to get big reward in the slot machine and seem to show heavy gambling rush in his eyes causing Biscuit to neck chop him to make him stop.
A stark contrast to his best friend Gon, Killua is highly mature in both thinking and emotion in which he can keep his anger in check and maintain rationality better than Gon even when facing a terrifying experience like the death of Kite, while Gon gives in to his rage and loses his logical thinking.
Killua is a member of the Heroes Coalitions and is part of the Dream Team. He also attends the Vanguard Academy as a student.
XP4 Heroes Coalition - Kick-Off!
In Chapter 11, Killua, alongside his team, the Dream Team, infiltrated the Bennington Adam's All-Boys High School in hopes of turning the students of the school in a new leaf. After defeating a group of students, Killua and everyone met up with the school's leader, Akira Nova. After Medaka Kurokami challenged Akira in a one-on-one fight, Killua and the others took a step back as they watches their leader takes on Akira.
Killua has all the benefits granted by his status as a Hunter. Furthermore, as a member of the Zoldyck Family, he has vast wealth at his disposal, although he needs his father's or his grandfather's permission to use them. His family name alone is enough to scare the ones that know what it is associated to. Killua has been trained since birth to become a human weapon, and is recognized by his family to be the most talented assassin in the entire history of the Zoldycks. When he took the Hunter Exam the first time, he was the fourth most powerful applicant (after Gittarackur, and, by his own admission, Hisoka and Hanzo, although that was without entering his "assassin mode"), and the one that Satotzbelieved would pass. Up until the Hunter Exam, he did not hesitate a second to kill, but after meeting Gon, this tendency subsided; still, he is not afraid to resort to extreme means when circumstances demand it. Like his friend Gon, Killua has an astounding natural talent that enables him to learn at a fast rate and allegedly ad infinitum, a characteristic that piqued Hisoka's interest. His potential extends to Nen as well, as noted by Wing and Bisky. Although he primarily fights with his bare hands, Killua is able to use any kind of weapons, but the only one he employs consistently are his custom-made yo-yos. When he tried to prevent the Selection, he was so confident in his strength that he claimed that tanks and fighter jets would be useless against him, and in fact he was able to effortlessly subdue a military unit comprised of at least four tanks.
His training endowed him with near immunity to poison, high tolerance to electricity, great agility and physical strength, advanced armed and unarmed combat and stealth techniques, which he acquired at a very young age. His intellect and exceptional analytical skills are equally remarkable, and it is often through strategy that he can defeat opponents who are stronger or more experienced than him. He is also able to walk without making a sound and sleep with a larger part of his brain awake than normal, so he can avoid attacks even in his sleep, even if they come from an armed, albeit weaker, fellow Hunter. After leaving Greed Island, due to his prowess in Nen, Killua became able to blend with nature more easily, which allowed him to find multiple new species of animals at a rate that astounded Kite's companions.
Preternatural Perception: Killua has proven multiple times to be extremely perceptive, whether by gauging a person's approximate power or by detecting their aura or gaze. He first demonstrated this by sensing Hisoka's bloodlust when it was still subtle. He could tell at a glance that Majtani was not as strong as he pretended to be, and offered Gon an estimation of how he stacked up against Hisoka, Hanzo and himself in terms of combat ability. He could also tell at a glance that Machi and Nobunaga were way out of his and Gon's league, unlike Leorio and Gon himself. His corollary that the stronger the opponent, the better they are at hiding their power turned out to be true, occasionally causing Killua to severely underestimate his adversary. However, as he honed his Nen abilities, his guesses became more accurate, and he notably sensed Netero's power, where as he had downplayed it in the past. He is extremely aware of his surroundings, as he managed to detect Meleoron's presence in spite of the latter specializing in erasing it. He is also able to sense the gaze of others even if their aura is hidden.
Enhanced Strength: Killua has displayed his strength on several occasions. Before he learned Nen, he was able to open a 16-ton gate and after he learned Nen, he opened the 64-ton gate. He can easily lift boulders several times his own weight and bisect massive trees with a single strike. He was able to rip off Rammot's head with one swift motion and crush it in his hand, as well as to pierce the exoskeletons of two Chimera Ants with his bare hands and minimum aura expenditure.
Master Hand-to-Hand Combatant: In spite of his young age, Killua is an exceptional melee fighter and master of innumerable unarmed combat techniques. The difference in experience between assassination and a proper fight initially prevented him from making the most of them, but he soon improved to an astounding degree. He countered Sub's assault despite the latter having a superior output and his own hands being unusable. During their duel, he goaded Sub into striking him in a certain way by pretending to have an imperfect guard. His fighting style, which is extremely versatile, aims at dealing the maximum amount of damage in the shortest time possible, striking critical points and making ample use of lightning-fast submission holds to incapacitate or kill the opponent. He can knock out a person by striking a sensitive spot on their neck while moving at high speed, a feat which requires superhuman levels of precision. Killua is particularly skilled at finding patterns in the fighting style of his adversary and at figuring out their weak spots, and at using them to exploit or create openings. He rarely resorts to combos, preferring to land single, critical strikes or to maintain a safe distance from more powerful opponents. After the removal of Illumi's needle, he became more assertive and prone to deadly blitzes, making the most of an opponent's distraction of vulnerability even if it means chasing them. Due to the Zoldyck philosophy of never putting their lives at risk while fighting, he was also taught a wide array of defensive and escape tactics. He seems to prefer to dodge attacks rather than block them, sometimes using the foe's charge to reposition himself in their blind spot, but he also has a solid guard.
- Killua is the first character from HunterxHunter to be introduced in the AWA fics.
- In the AWA fics, Nina Sakura sees him as a little brother. Despite his annoyance, he admitted that he enjoys her accompany.
- In the AWA fics, Killua has no idea that Mio Akiyama has a crush on him.
- Killua's name is probably derived from the English verb "to kill".
- Out of the four main protagonists, Killua is the youngest; during the first phase of the Hunter Exam, he confirms that his age is almost 12, just like Gon. Gon's birthday is May 5, while Killua's birthday is July 7, making Killua younger than Gon.
- Killua is reported to be four centimeters (about one inch) taller than Gon, but the two are often seen being the same height.
- His favorite food are ChocoRobo-kun chocolate balls.
- He is nicknamed Kil or Killu by his family. However, neither the Zoldyck's employees nor Gon and his friends use this name.