The Dark History of the Reincarnated Villainess Vol. 1 (manga)

Konoha Satou has a dark history. Although she's not the only middle schooler who's dreamed about romance and adventure, Satou takes it to the next level when she writes herself into a reincarnation fic as the main heroine. But little does she know, her fantasies will become reality when she wakes up in her Dark History! There's just one small complication...Instead of playing the role of heroine, she's the most despicable villainess--Konoha's little sister, Iana. Which means if she wants to avoid tripping her own death flags, she'll have to remember every last detail of her story...