The Simple Life of Killing Demons - Chapter 10Book 12:

After rebirth, she, who used to be a top international spy, becomes the eldest daughter of the Fengs, a fat girl who is ugly and foolish in the eyes of the ordinary people.
Mastering Royal 18 Saber Moves and Purgatory 9 Palms, she rose to fame with the martial arts of Demon Cook.
Upon an imperial edict, she was ennobled as the wife of Lord Cen, and then suffered various intrigues and plots…
She proved herself to be a real overmatch and a true genius to the world…

The plague of insects descended overnight. As an ordinary person without invincible powers and extraordinary exercises, facing blood and death, what should we do at the critical moment of life and death?

(I am a reasonable party, but the novel needs appropriate YY, please do not excessively investigate the rationality of the background in a razor-sharp way.)

- Description from novelbuddy

The second prince has come of age. To celebrate the advent of such an occasion, the search for a suitable bride began. My younger sister was expected to go to the Royal Palace as a candidate. However, despite this, she eloped the day before her departure. I, the older sister she left behind, looked almost exactly like her – so much that we were often mistaken for twins…

One month, right? For just one month, shall I substitute in for my sister?

“O, Hero!” With that cliched line, Kazuya Souma found himself summoned to another world and his adventure–-did not begin. After he presents his plan to strengthen the country economically and militarily, the king cedes the throne to him and Souma finds himself saddled with ruling the nation! What’s more, he’s betrothed to the king’s daughter now…?! In order to get the country back on its feet, Souma calls the wise, the talented, and the gifted to his side. Five people gather before the newly crowned Souma. Just what are the many talents and abilities they possess…?! What path will his outlook as a realist take Souma and the people of his country down? A revolutionary transferred-to-another-world administrative fantasy series starts here!