Iiieahtoph is a female cat of the new and old Felidae breed. She is only shortly mentioned in the book: she mated with a male cat named Tomtom and he was killed by Pascal to prevent the alteration of the breed for this reason.
Trivia: As the other cats of the Felidae breed, Iiieahtoph is probably not interested of the genetic purity of her breed and it's likely that she was not aware of the death of Tomtom (another possibility it's that she was aware, but somehow kept to silence by the same Claudandus).