WARNING: Potential spoilers ahead. Expand at your own risk.
This character, at one point, had a whole story in my head that would have been a part 3 of the series. I never actually wrote it, because I realized it would have complicated things far too much. And, really, once the fairy tale has a Happily Ever After, no one wants to read about what came afterward. But, since you’re here, and since you asked…
In my head, owing to some sort of Faery involvement, Lyssette and Bastien were robbed of the story we all know and love. But they did get a second chance. Thanks to a benevolent Faery taking pity on them, Lyssette got an opportunity to alter the course of their lives. She sacrificed her (admittedly bleak) future to go back into the past and rewrite the story from the beginning. She became her own fairy godmother, so to speak, setting her man on the path that would bring him to her rescue. The only catch was, she could not be seen, which is why her face was hidden throughout the duette. Her appearance, was the duality of her nature—one half young and hopeful, the other half old and defeated, with nothing left to lose.
Pretty neat story line, if I do say so myself. It would explain why the Hag is so focused on Bastien when they first meet in the series, and why she’s so adamant about him not seeing that last card the second time around. From her point of view, things have to progress a certain way for the correct future to happen. If you already read the book(s), you’ll remember a sneaky allusion to this alternate reality in the first one, where the prince is visited by the Hag one night and she shows him a future in which he never meets Lyssette. This vision becomes pivotal to his actions going forward, as had everything the Hag had done up to that point. Score another one for the damsel getting stuff done!