MTL - Naruto, Make Senju Great Again - Chapter 713

An ordinary (?) grandfather, Choi Chuntaek. In an effort to protect his granddaughter, he started the virtual reality game 'Arkstar.'

Then... he accidentally obtained a legendary class?

Three years ago, Yun Qing Yan fell into the Immortal Realm from the mortal realm. Three thousand years later, he became Divine Emperor Yun who shook the entire Immoral Realm. Breaking through the void and returning back to the mortal realm, Yun Qing Yan discovered that only three years’ time had passed here. “In the past, I did not possess the power to protect the people I hold dear. Now, I want the entire world to grovel at my feet.”

- Description from Novelupdates

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

The sky was painted gray forever. The light of the sun was restrained. The darkness of the night was deeper than ever. At such a time, he belonged to a class people didn’t even recognize as ’human’. He was at the bottom of the social stratum, a slave. And when his only family was taken away from him... he no longer had a purpose in life. Yet, he clung to life because of his promise. And he set an impossible goal for himself, just so he’d have an excuse to live. When he finally reached a place he never expected to be, in pursuit of a purpose he expected to fail and die miserably trying to fulfill... he awoke to a night that would change his entire life. He was an insignificant fly, a mere speck in the destruction of the Empire. But he... survived. And, despite being a slave, he gained the blessing of a king. Or rather, the curse...