폭군의 간신이 되었다

I Became the Tyrant's Dishonest Adviser

A customer service employee one moment, then an adviser to the tyrannical emperor, Cardan Zeon, the next. Our heroine was suddenly transmigrated into the body of Duchess Erina Valois, a side character who dies a tragic death at the emperor’s hands in a novel she was reading the night before. So despite all the confusion and chaos, one thing is for sure. If Erina is to survive under this tyrant, she will have to get her act together ASAP! Though, strangely enough, she gets a sense that there is more to their relationship than what was described in the novel... (Source: Tappytoon)