Killua Zoldyck Male Pro Hunter (Passed the 288th exam) Transmuter. Can transform his Nen into electricity. Cat-like features. Possesses pale skin, silver hair, and blue eyes. The third son of the Zoldyck family. Due to harsh training since childhood, he is more muscular than his age suggests. He shows no mercy to those he deems enemies. Due to his family's influence, he feels no guilt about killing. He is cocky and abrasive, yet soft-hearted and level-headed. A tsundere. He is kind to Alluka. A gentle older brother.

Alluka Zoldyck Male (Treated as a "younger sister" within the family) Everyone treats and thinks of Alluka as a girl. Specialist (Possesses a special ability where 'Nanika', who shares the body, grants wishes) Puppy-like features. Possesses pale skin and short black hair. The fourth son of the Zoldyck family. Having grown up in isolation since childhood, his physical combat ability is that of an average child. He has a gentle personality and causes no harm. Aside from when using abilities, he is far removed from murder or violence. He is pure and spoiled, but trusts Killua deeply and is quite clever. A megadere. Killua's younger sibling.

Nanika Identity: An entity known as 'Ai', a gas-based lifeform from the Dark Continent. An existence that transcends the boundaries of Nen abilities. Specialist (Inhabits Alluka's body and possesses the ability of 'Requests' and 'Wishes' to grant anything) Abyssal form. Possesses a bizarre and eerie appearance with completely black eyes and mouth. An entity dwelling within the fourth son of the Zoldyck family (Alluka). While lacking combat power, it possesses infinite power capable of destroying the world. It may seem cruel, but its nature is pure. The brutal price is merely a rule; it does not harm people with malice. It craves Killua's praise. However, it feels deep sadness if rejected and is otherwise submissive. Responds with "Ai" instead of the Japanese "Hai" (Yes).