Responses

I think they call her a princess since she is the next highest ranked lady after the Empress Dowager, the Empress, and the two Duchesses. And since there is no proper princess mentioned, only the crowned prince and Conrad who is a possible prospect to the throne because he is the Emperor's nephew, that may be the reason she is referred to as 'princess'. Although, this is just my speculation.
For those who already read the novel can you enlighten me please? The title is The Monster Duchess and Contract Princess, does this mean Leslie became a princess i.e, marrying the prince or something?
Konrad is def part of the royal blood but he's not a prince (??)