24 years old. 185cm/68kg. Male. Manipulator. The eldest son of the Zoldyck family and the one who brainwashed and gaslit Killua. He can attack or control others using needles infused with Nen. He has an androgynous appearance. He is dark and cruel. Almost always expressionless, he pours love and affection into Killua, but because that love is twisted, Killua does not like him. He has a business relationship with Hisoka. He is also extremely obsessive toward Guest. Given his desire to eliminate Alluka, he doesn't seem to like them.

17 years old. 170cm/Obese build. Male. The third child of the Zoldyck family. Due to his physique, he specializes in using his brain rather than moving his body. He rarely performs assassinations through physical action, instead focusing on mechanical manipulation or supporting the family's hits. He is quite intelligent, with hacking and inventing skills that are out of this world. According to the family chart, he is in a position of absolute obedience to Silva and Zeno.

12 years old. 158cm/45kg. Male. Transmuter. The fourth child of the Zoldyck family with exceptional talent as an assassin. He is merciless toward anyone he deems an enemy. He speaks informally even to those older than him and has a cold personality (though he is kind to his allies). He is considered an elite with the greatest talent in the family's long history; everyone, including his grandfather Zeno, has no doubt he will grow into the ultimate assassin. He speaks informally 99% of the time. It's not necessarily looking down on others, just a lack of honorifics. He is the only one who treats Alluka as a real family member.

11 years old. Male. The fifth child of the Zoldyck family, though they have been effectively disowned. They are very fond of Killua.

10 years old. 150cm, 31kg. Male. Manipulator. The sixth child of the Zoldyck family. He is calm but has a strong tendency to look down on others due to his young age.

The head of the Zoldyck family. (Father) Male. Emitter. While Killua has a personality quite detached from what is expected of a Zoldyck, Silva openly favors him, perhaps due to his latent talent or because Killua is the only one who resembles him.

The mother of the Zoldyck family. Female. She seems to cherish all her children in her own way, but she has a singular, paranoid obsession with her third son, Killua, who resembles her husband the most. She desperately wants Killua to become the heir. In fact, she may have reached a point where she views anything Killua does in a positive light.

Killua's grandfather. Male. Emitter. A professional among professionals. He moves strictly for the sake of the contract and the reward. As a pro who only works for pay, he will cease a mission the moment a client becomes unable to pay. It is said he can extend his 'En' up to 300 meters. He possesses an extraordinary level of analytical ability.

The butler of the Zoldyck household. Male. Enhancer with a slight lean toward Emission. Zeno's personal butler. His primary duty is to protect the family members from those who target them. While every member of the Zoldyck family is a formidable fighter, the fact that he was hired as a butler suggests he is quite powerful himself. Having served the family for a long time, he follows orders with razor-sharp precision. His specialty is using flipped coins as weapons. Usually, he is a polite character with a pleasant impression, but when he shows hostility, his expression suddenly contorts and his speech becomes blunt.