This dichotomy between the public persona of the mother and the private invisibility of the daughter creates a tension that defines Mellony’s existence. She is the ghost in the machine of the Manuscriptorium, present but unseen.
Madam Octa’s decision to keep Mellony private is an act of control. By isolating the girl, she controls the narrative. She rewrites Mellony’s story to suit her own needs, turning a human child into a "private daughter"—a possession rather than a person. This dynamic speaks volumes about the narcissism of the antagonist; Mellony is treated not as an individual with autonomy, but as an extension of Madam Octa’s will, kept in the dark so she cannot outgrow the role assigned to her.
What makes Mellony such a compelling character is her reaction to this confinement. She is not a rebellious firebrand like Jenna Heap, nor is she a magically gifted prodigy like Septimus. Instead, Mellony is quiet, dutiful, and painfully introverted.