Elisa
About
Agrippina reveals that Elisa is a changeling, a fairy in a human body. Equal parts powerful and unstable, she must gain control over her magic so she doesn't become a threat to herself and others. Agrippina offers to take her as an apprentice and enroll her at the Imperial College of Magic with Erich's indentured servitude as payment.
Fairies are naturally possessive and favor blond hair and blue eyes, explaining her fixation on Erich.