Kingdom's Bloodline - Chapter 669 magician

[You have entered the dungeon at Gwachun Station’s 1st Exit.] When former high school student Kang Woojin finds himself returned back to Earth after being forcibly summoned to a foreign planet for 20 years, he soon finds that Earth is not the same, normal place as he once remembered it to be.

The most famous deed of this princess was her words to her younger brother Liu Ziye.

When he became emperor, she told him, “Although your highness and I are of different sexes, we are the children of the same father. Why can you sleep with so many different women, while I must be only with my husband? This is so unfair!”

And after the Emperor Liu Ziye heard his elder sister’s words, he ridiculously thought it made sense. So he immediately corrected his “wrong ways” and painstakingly selected thirty handsome youths for her to enjoy.

Chu Yu awoke in the princess’s body and realized that she had obtained a male harem of three thousand; should she take just one to drink, or keep all of them?

- Description from Novelupdates

A failed investor from 2017 got drunk and woke up in the 1980s. China is just opening up, and the economy is blooming. There is also the dissolution of the Soviet Union, the bursting of the Dot-com bubble and other financial crisis. He used his knowledge of the future and slowly build up his empire.

After reincarnating as Zhou Xuanji, the prince of an empire, he thought that he would be able to live a worry-free life of luxury. He did not expect to be involved in a rivalry with the Empress herself, who forced him to escape from the palace.