Board Thread:Questions and Answers/@comment-25951143-20150101110046/@comment-28018961-20160807032312

Okay, so it's confirmed that her biological sex is male(I honestly think it's really stupid that I need to specify that 'biological', but...), so we know now that the only ways she could be female in any way are:

Nanika is seperate from Alluka, and has his/her own sex apart from Alluka's--but that might be unlikely since Killua was more partial to Alluka, not recognizing Nanika as much, and he referred to Alluka as her, so it's a possibility, but probably not.

Or she could be trans.

Are there any other possibilities?