Elf Tensei Kara no Cheat Kenkoku-ki - Chapter 15Book 5: -3: The Broken Empire

The ill-fated high school student Liu Yuan obtained the inheritance of the top civilization in the universe and changed his own destiny. He also used many powerful technologies in the inheritance to lead the Chinese nation to rise in the universe.

- Description from novelbuddy

The Mc reincarnates in a world of magic and adventure as a Leech, follow his adventure in this mysterious and exciting world as he goes from the weakest creature to the shadow being that everyone is afraid of. Will he pursue the path of strength alone? Or without realizing it he will become the king of the greatest empire that ever lived.

To pass as an imperial concubine, one must be professional.

Actually, the profession of an imperial concubine is pretty good. The emperor will accompany you in eating and drinking, and even pay you for it. What’s not good about that?

Zhang Ye was originally a mundane college graduate with aspiring dreams to become a star, but unfortunately has below average looks and height. However one day, he woke up and suddenly found himself in a parallel world!