Naruto: Can't Use Ninjutsu? I'll Create the Strongest Fighting Style - Chapter 9: Hokage’s Visit

A man was transported to Ancient China and eventually became a servant of a declining household without a male heir. He utilized his wits and modern knowledge to help the household and eventually become trapped in the sea of political turmoils of the period.

- Description from Novelupdates

High school student Mikoshiba Ryouma was summoned to a different world in the middle of a war. Sensing the malice from the one who summoned him (a summoner of the O’ltormea empire), he uses his martial arts to run away, killing important people of the empire during his escape. After the escape, he rescues two twin sisters from the hands of thieves. The sisters who can use magic, swear to serve him as subordinates. Thus, Ryouma begins his journey on the path of the supreme ruler.

Humanity had finally ended the war with the Demon Race and sealed them away, forever.However, they now have to face the treat of the Shadow World, an equally dangerous threat to their civilisation under the rule of the Emperor!Facing only misfortune from a young age, Nikolaus Reinhardt never expected anything good to happen to him.But his world completely changed when he awakened as an Ascendant, and accidentally summoned a member of the Demon Race in his house.Just because he messed around with a god damn book!

A next-generation virtual online game, a hardcore gamer, a glitch that shouldn’t have existed… By sheer coincidence, Meng Jingtian ended up being the sole player god in a game. Thus, while ordinary players worked themselves to death running missions for NPCs to win their favor, NPCs prostrated before him! While ordinary players almost vomited blood grinding for gear so that they could solo bosses, the king of divine beasts kneeled before him, willing to offer its life and worship him. And while players went to suicidal lengths to trigger random events and lucky encounters, transcendent beings came to find him so that they could offer their precious treasures as tribute.