HIRATORI Kou

A younger sister who stakes her soul for her older sister. An older sister who swears revenge for her younger sister. Having lost her parents, her older sister, and her grandmother... the family that was her emotional anchor, Marquess Charlotte herself suffered scars that will never fade. Known as the "Cursed Unfortunate Lady," one day she makes a contract with a demon, offering her own body as a vessel to resurrect her older sister, Lieselotte, who was supposed to be dead. Eventually, Charlotte, together with Lieselotte the "other soul" residing within her exacts revenge on the culprits who murdered their family, one after another... https://mechacomic.jp/books/240013