Akuyaku wo Yametara Gitei ni Dekiai saremashita

Reincarnated as the duchess from a novel she wrote in a previous life, Lelia finds herself the villainous character who bullied her cold, expressionless, and beautiful stepbrother, Rudeus, to death. In order to avoid the worst case scenario, she takes good care of her brother, but for some reason he has approached her...?

(Source: Kadokawa, translated)