I find the use of 'princess' a bit jolting. To try and clarify things, Rozemyne is the adoppted daughter of the archeduke. So Lady Rozemyne.
There are royals in this story and we have gotten mention of them.
We might get to meet a princess though.
Thank you for the translation.
Translating hight Nobility is tricky, because of all the subtle local differences, but the daughter, adopted or not, of an Archduke
is a Princess, and sons Princes...
Archdukes/Grand Dukes are, very much, Royalty in their own right.
The thing about Rosemyne is that she is adopted into
high nobility. If her family were "merely" ducal she'd have to be adressed as "your grace", but she's much higher up the food chain, so it's "princess". "Lady" is several rungs lower.
In her position as High Priestess, she'd be addressed as "Her Eminence". Depending on whether people were talking to her as a priest or a high noble.
The only people who would address her as "Lady" would be people who are very intimate with her ( like her attendants )
in private if she allows it.
And Oiks who don't know proper etiquette, but they don't count as they're commonors who can't be expected to know better anyway.