Synopsis
Nanika is an entity sharing a body with Alluka Zoldyck. When it surfaces, Alluka's sclerae, irises and mouth turn pitch black and the mouth appears larger; Nanika's own form has never been seen.
When or how it came to inhabit Alluka is unknown — the two have shared her body at least since she was a young child, and the Zoldyck family remains in the dark about its nature. Killua once witnessed the transformation and asked Nanika directly how to reverse it, which is how he learned the general shape of its abilities.
It speaks in a terse, clipped register and, like Alluka, is deeply attached to Killua, whom it calls fondly by name.
Nanika can attach itself to a living being and coexist inside their body, taking control when certain conditions are met; its physical capabilities are simply those of its host — currently, those of an ordinary child. It is this power Killua turns to in order to save Gon. Voiced by Maaya Uchida.
