Anyone who insists that she uses they/them ONLY is weird. Many franchises use they/them for their canon transfem characters to degender them, the same way they use “gender:unknown” or “gender:???” to get around calling them female. It’s intentionally vague. People who insist that Mizuki is nonbinary rub me the wrong way because there’s no indication that she doesn’t identify as male or female, she’s VERY clearly transfem. The only reason people call her nonbinary is because of the “canon” they/them pronouns. Like I said, take a second to think about why a game would use neutral pronouns and language for a TRANSFEM character instead of she/her..