Two Faced Lover (A Black Butler/Kuroshitsuji fanfic)

A trained swords assassin who has lived life in complete and utter darkness, is finally freed by the Phantomhive family. To serve as not only a maid, but the lord of the manners second hit man.

After being contained in darkness for most of her life, number 17 gains a second personality that catches Ciel's interest. But he never realized, having a two faced maid would change his life.