There are of course a lot of options as to who she might be but in the beginning of the story she mentioned “grandmaster who knows me or my father” or something along those lines – though somehow I don’t see the reaction being so mellow if her father was Red Hemlock. I’m also a bit confused about her behavior here because I also assumed her to be *much* older than the 35 she mentioned. Especially when she says she has been doing stuff decades longer than the others when they faced the beetle. Also, she keeps acting like the others were children compared to her, like you said.

I always entertained the idea that she is the Red Hemlock. I mean she knows fancy dark arts and alchemy. There are so many options depending on what alchemy and said dark arts in this world are capable of so why would using alchemt to have a youthful body or changing your gender be out of question? I guess you could even escape death by transferring your mind/soul to another body. Maybe this body is in fact 35 but the mind/soul is not.

Both seem pretty evil options since in the latter you would need to take over someone else’s body (unless it was a vat clone) while in the former you would have someone die in your place since someone got executed (unless it was again a vat clone). Your idea is more intriguing though. Clearly she has some knowledge of the subject.