Tensei Akujo no Kuro Rekishi summary: Konoha Satou is the author of "Dark Past," a romantic adventure-style fantasy novel she wrote in middle school about the life of Konoha, the daughter of a count who fell in love with her knight. One day, her mother found out about "Dark Past," but as Konoha ran out of her house she got into a traffic accident and died! When she opened her eyes, she found herself in the world of her own creation as Konoha's younger sister, Iana, a character she created to be the greatest villainess of all time! Somehow, she's been reborn as Konoha's sister? (Source: Hakusensha, translated)