Broker - Side Story: Gravitic 2

A skilled but unfortunate modern-day assassin was killed in a freak accident. However, he soon found himself summoned to another world by an evil wizard, who had him possess the body of a boy as an experiment. After successfully planning the evil wizard’s downfall, he used the wizard’s body as a springboard to gain influence and power in his new world.

- Description from Novelupdates

This novel is also known as Don't Mess with the Dark Princess

When trash becomes a genius—one word: Fierce! Two words: Two-faced! Three words: Too heaven defying!

She is the foremost and outstanding armament refining master. Passing through a dynasty, and became a publicly humiliated and bullied Third Young Miss. Ancient beasts, too outrageous? Obediently become a docile pet, or I’ll make you into soup!

Ninth rank talent, rare talent in a thousand years? She was born with a godly constitution, crushing all geniuses!

Peak level Profound Grade Armament, beyond priceless? Sorry to embarrass, but the bowl she uses to feed the cat is already at the God Grade….. she possessed a pair of eyes that could see through everything, yet she couldn’t see through—him!

Merely exposing his demonic smile, Prince Mou lightly loosened his belt: “Can’t see through? Do not fret, you can slowly view when you return to the room. I’ll allow you to scrupulously inspect from head to toe.”

- Description from Novelupdates

As we all know, there is a force that must not be messed with in the Southern Region, thatched cottage.

Among them, the eldest disciple is the Qingyun Sword Master of the Southern Region, with a mastery of swordsmanship.

The second disciple, the Eternal Empress, leads an era.

The third disciple is a great Confucianist in the world, and the star of Wenqu came down to earth.

The fourth disciple, the reincarnation of the demon god, suppressed Jiuyou.

…

Lu Changsheng: Me? I am nothing special, just their master.

- Description from novelbuddy