Ermellia - the wife of Hereward, and thus the Duchess of Ellander. She is said to be especially fond of Nenneke's aphrodisiacs.
She is mentioned in the short story "The Voice of Reason"
“
Tell that to his wife, the noble Ermellia, adding that if she wants to continue receiving an uninterrupted supply of aphrodisiacs from my pharmacy, she'd better calm her duke down.
”