Board Thread:Manga Discussion/@comment-32189512-20180216130910

Throughout the manga Togashi has created non-binary characters. That is a fact. Examples: Kurapika, Kalluto, Neferpitou, Tubeppa.

Alluka is one of them. Alluka is supposed to be male, yet Killua refers/treats Alluka as a female. Not to mention Alluka dresses like female. That's why her gender and pronoun are using female/feminine, although it is likely she is biologically a male. 