Heroine na Imouto, Akuyaku Reijou na Watashi

When Christina, the beloved daughter of a duke, meets the girl who will become her adopted younger sister, something extraordinary happens—she regains memories of a past life. These memories reveal that her new sister Mishuly is connected to a mysterious story, one that seems to hold clues about their future. Rather than following the dark path laid out in those memories, Christina chooses a different route, becoming an adoring and protective older sister who cherishes Mishuly above all else. But as their bond deepens, Christina begins to suspect that the story she remembers may not be as simple as it first appeared, and that the happiness of her beloved sister might require difficult choices. This is a touching tale of sisterly love, where one girl's devotion to her sibling transcends the boundaries of fate itself.