The Queen's Blade: Lady Phantomhive
Before the Phantomhive tragedy, before Ciel Phantomhive was born, Rachel and Vincent Phantomhive had a daughter. Due to an illness, they had her sent off somewhere else for her treatment. Angelina, Rachel's sister, heard about the child's condition and pursued to become a doctor, although it was against her parent's wishes.
Later on, Ciel was born and the Phantomhives were very happy. they hid the fact that they had another child before Ciel, deciding to wait for the right moment to tell everyone. But then the tragedy happened...
her life is kept secret until. . . . .