RE: Monarch - Chapter 1-2. Ignis I

Born into a unique world where villages fight to gain power and control, the main character, Shi Hao, is a genius blessed by the heavens born under the poorest of conditions. His clan, however, has a mysterious past. To rise up and become the genius he is meant to be, the clan goes through every effort to aid his cultivation as they battle through fanatical monsters and engage in power struggles with other clans. His journey will bring him through unknown lands until he is able to become a person that can truly shake the world.

A con-man and policewoman that are legends of their respective professions suddenly die, then are reincarnated and return to the Tang Dynasty of ancient China as little kids.

Accepting their second chance and forced restart, they choose to use the modern knowledge and specific talents that they have in their previous lives in order to live comfortably in this new life.

- Description from Novelupdates

Wang Xiao was compelled to descend from the mountain by his master, with his intrinsic energy cloistered, and a lovely woman erroneously believing him to be her betrothed. In a bid to safeguard his mistakenly assigned fiancée, he resolved to remain in the school teeming with enchanting beauties. With the same intent to defend his intended, he managed to transform the currents of power within the city.