The Key-Mistress at the White Stone Palace is Selia's mother.
The key-mistress's only child, Selia, displayed signs of people-speaking at an early age. Although it is likely she didn't know specifically that her daughter had a gift of language, she did realize that Selia was talented with words and seems to have used the girl's skill to both their advantages whenever possible.
Eager to improve her relationship with the Crown Princess of Kildenree, Anidori-Kiladra, the key-mistress invites her to have tea with her and her daughter, Selia. She is honored that her daughter was chosen to be the first -and only- member of Princess Anidori's retinue and thanks Ani for being not only a good mistress, but also a good friend to Selia. However, despite Selia's skill with words and the key-mistress's eagerness to improve her relationship with the Crown Princess, the tea is still doused in awkwardness and ends with Ani clumsily excusing herself to meet with her father.
Unfortunately, the king is fatally injured in a horse riding accident later that very day. The key-mistress most likely attends his funeral and hears along with the rest of Kildenree the Queen's announcement that she has transferred Anidori's birthright, being heir to the throne, to her son Calib-Loncris. Instead, Anidori will be sent to the neighboring country of Bayern to marry their Crown Prince. Selia, as Ani's lady-in-waiting, will accompany her as part of the princess's escort. But before she embarks on her journey, Selia asks her mother to steal a royal seal for her. Either the key-mistress knows about her daughter's plans and approves of her efforts to gain power and improve her status, or she is merely persuaded by Selia's people-speaking skills to perform the theft for her.
It is extremely likely that she never saw her daughter again. She is presumably devastated to hear of her only child's death.
- "I have begged my daughter for some months to invite you to our apartments. You have grown as tall as your mother, though not quite as pretty, and I wonder, since you always seem to be quite busy, if you have yet learned what duties are most important to you station?"
- Do you not think, Crown Princess, that it is inappropriate for a princess to ride a stallion? Should you not ride a nice, gentle mare or gelding? Are you not afraid that you will break your crown?"