MTL - I, a Demon Slayer Girl, is Invincible! - Chapter 217

After the disaster, there wasn't enough food, so I used my superpower to farm, striving together with my childhood friend for a better life.

Eira Kingston, a feared assassin, never imagined that death would lead her to transmigrate into the body of Ephyra Allen, the disgraced first daughter of the once-powerful Allen family. But what shocked her even more was the soft mechanical voice in her mind, addressing her as “master” and informing her that her soul had returned to its original body.Eira dismissed the strange voice, thinking she was having a post-death hallucination. But waking up in a hospital, with memories that weren’t hers flooding back, she was forced to confront the truth.Ephyra’s life had been nothing short of a nightmare. Despite being the legitimate daughter, she was labeled a bastard, shunned by all, and overshadowed by her scheming stepsister, who had stolen the love of her father and her betrothed. To make matters worse, the wealth and status the Allen family enjoyed were all thanks to Ephyra’s late mother, and the only reason she hadn’t been discarded entirely was due to her mother’s inheritance, locked away until she turned eighteen.But Eira wasn’t one to be defeated by circumstances. If she was going to live Ephyra’s life, she would do so on her own terms. She would destroy those who had caused Ephyra pain, claim the inheritance that was rightfully hers, and find out who was behind her own death. Because if there was one thing Eira knew how to do well, it was to survive—and make her enemies pay.However, being a high-schooler with nothing to her name wasn’t enough. As Ephyra, she’s powerless, but as an assassin, she’s lethal. Still, even that wasn't enough until she became the contracted wife of Lyle Aelion—a powerful, enigmatic figure in the business world with a secret illness. And it turns out, the only thing that can relieve him is her scent.

MC (female protagonist) dies in a plane crash and wakes up in the body of a beautiful but corrupt and lascivious prime minister in ancient times, Zhang Qinglian. As circumstances decree, he (she) cannot reveal that the original owner’s soul is gone else calamity might occur. So he (she) decides to walk a righteous path, determined to help the lovely but simple little emperor rule the country. Not backing down after facing torture, not losing courage, destroying rebellions and facing off with scheming princes.

- Description from Novelupdates

He is the master of six kingdoms. As long as he wanted, his cavalry is ready to wipe off any country.