Who Is Killua Zoldyck?

Killua Zoldyck is often considered as the deuteragonist of the manga and anime series Hunter × Hunter, though many fans consider Killua’s character arc to be more in line with that of a primary protagonist. Killua is a member of the infamous Zoldyck family of assassins. He rebelled against his family to become a Hunter and the best friend of the traditional primary protagonist, Gon Freecss. He is a skilled assassin with extreme tolerance for poison, pain, and electricity, and possesses extraordinary agility and strength.

Appearance

Killua is an adolescent boy with spiky white hair, a slim build that becomes more muscular as the series progresses, pale skin, and blue eyes. His eyes are unique and seem to change shape to be narrower and sharper when he's threatening or killing someone. He is often attributed with wearing a casual, loose-fitting outfit consisting of a blue turtleneck sweater, white T-shirt, blue/gray shorts, and flat-soled shoes. However, more so than any other character in the series, Killua has a tendency to wear a wide variety of outfits

Personality

Killua is a complex character whose personality is defined by a conflict between his trained coldness and bloodlust as an assassin and his innate kindness and loyalty, particularly to his first true friend, Gon. Raised by the world's most deadly assassins, he possesses an intelligent and logical mind, yet struggles with a perverted sense of morality and low self-worth. As he grows, he seeks freedom, purpose, and a life of his own, ultimately showing deep empathy and a fierce protectiveness towards those he cares about.

Background

Killua is the heir to the Zoldyck family, a legendary lineage of assassins. The Zoldycks are a clan of elite assassins who reside on Kukuroo Mountain. Every member of the family is subjected to brutal training from birth to develop superhuman abilities. Killua is the middle child and is considered the most promising assassin of his generation. 

His immediate family consists of his parents, Silva and Kikyo, and his four siblings: Illumi, Milluki, Alluka, and Kalluto. Killua's older brother, Illumi, mentally and psychologically conditioned him to believe that he could only excel as a killer. Illumi even placed a Nen needle in Killua's head to influence his actions and decision-making by instilling fear and causing him to flee from stronger opponents.

The sole positive relationship he had growing up was with his younger sister Alluka, whom the family feared and locked away due to her mysterious wish-granting abilities. Killua was the only one who showed her genuine affection. Tired of a life of constant killing, Killua finally rebelled against his family and sought a new path.

At the age of eleven, he attacked his mother and older brother, then ran away from home to take the Hunter Exam, simply for fun. During the exam, he met Gon Freecss, and the two quickly became best friends. Gon's friendship was a turning point for Killua, who had never known what it was like to have a friend or a purpose outside of his family's plans. With Gon's help, or perhaps in spite of Gon’s descent into guilt-fueled rage and vengeance, Killua eventually broke free from Illumi's control by removing the Nen needle from his head. When last Killua was seen in the series, he had decided to leave Gon to travel the world and protect his sister Alluka, devoting his life to her happiness.

Powers and Abilities

Killua Zoldyck's primary abilities include superhuman physical attributes (strength, speed, agility, durability), an immunity to poisons, and mastery of Nen, particularly his transmutation-based electrical abilities. 

Superhuman Characteristics and Assassin Skills

• Enhanced Strength, Speed, and Agility: Killua possesses strength, speed, and agility far beyond that of a normal human, making him a formidable physical combatant. 

• Immense Durability and Stamina: His physical constitution allows him to withstand significant damage and endure prolonged physical exertion. 

• Immunity to Poison: As a result of his upbringing and torture, Killua is naturally immune to poisons, making them ineffective against him.

• Claws: Killua can turn his fingernails into sharp, deadly claws capable of piercing most materials. 

• Skilled Combatant: He is a master of hand-to-hand combat, having been trained as an assassin from a young age. 

• Acrobatics: Killua demonstrates exceptional balance, coordination, and agility, allowing him to perform complex acrobatic maneuvers.

Nen Affinity and Abilities

Nen (念) is a fundamental power system that allows individuals to control their life energy, known as aura. By manipulating their aura, Nen users can create unique supernatural abilities called Hatsu, enhancing their physical capabilities or creating complex, personal powers. 

• Nen Affinity: Killua is considered to have an affinity for Transmutation, but series author Yoshihiro Togashi, has shown Killua to be part way between Transmutation and Enhancement, indicating that he is primarily a Transmuter with a strong leaning toward Enhancement. A Transmuter is a type of Nen user who can transform their aura into a substance. In Killua’s case, it is typically electricity. 

• Electric Aura: He transmutes his Nen into electricity, allowing him to generate and control electric currents. 

• Lightning Palm: By channeling electricity into his hands, Killua can deliver a powerful electric shock to an opponent through physical contact. 

• Thunderbolt: He can project a bolt of lightning from his fingertips, which is used to stun and paralyze opponents, though it deals little physical damage. 

• Godspeed: A Nen ability that transforms his aura into electricity, allowing him to vastly enhance his speed and reaction time by bypassing his normal nervous system, enabling superhuman movements and lightning-fast defenses and attacks.

  • Whirlwind: In this state, Killua's aura automatically moves and reacts, allowing him to evade attacks and move with incredible speed and agility without conscious thought. 

  • Speed of Lightning: This ability allows Killua to move at extreme speeds, making him appear as a blur or even teleporting across short distances.

Goals and Reputation

Killua's primary goal at the start is to break free from the Zoldyck family's control and the assassin life they forced on him. He joins Gon in the Hunter Exam hoping to find a new path and discover his own identity. He wants to stay by and protect Gon, finding emotional fulfillment and a sense of belonging through their friendship, which helps him find himself. 

The most significant shift in his goal occurs after he rescues his sister, Alluka, from their family. He realizes that Alluka's powers and her imprisonment make her vulnerable, and his new mission becomes to keep her safe and show her the world she was denied. By the end of the Chimera Ant Arc, Killua decides to leave Gon to care for Alluka and protect her from their family.

Killua is known for his brutal efficiency and ruthless nature, a product of his upbringing by the infamous Zoldyck assassin family, but this side becomes less prominent as he forms bonds, especially with Gon, inspiring his own pursuit of justice and adventure. He is widely popular among fans for his character growth, competence, and relatability, even becoming more likable than Gon in certain story arcs.