Reborn in Naruto As Madara's Grandson - Chapter 15: Academy

The little handsome son-in-law passed through a world as waste material and the husband of a wealthy family. But because of his lacking aptitude, the wealthy family had driven him out. So he worked hard and found a more powerful family’s thighs to hold onto. Soon enough, he became the strongest son-in-law and husband in history.

In this world, it was impossible to practice martial arts. It was futile so he might as well take advantage of his wife’s thighs and maintain a comfortable and leisure lifestyle.

He’ll train his wife to become the strongest and best person in the world.

“Whoever dares to provoke me, let my wife kill you!”

- Description from Novelupdates

After transmigrating into a weak noble body, Marvin discovered that he was familiar with the world, this was the game he played in his previous life and… Damn! He only had six months before the Great Calamity!

Li Xuan traveled through the world of immortality and opened the apprentice system, and both apprentices and apprentices could be rewarded for upgrading.

【Ding! Accepting apprentice Qin Yue, reward you: Innate Divine Power]

【Ding! Accept the apprentice Zhao Tian, ​​reward you: call the wind and call the rain]

【Ding! Apprentice upgrade, reward you: space shuttle]

….

Li Xuan, who accepted a bunch of apprentices, evolved infinitely in seclusion.

Ten years later, the Devil Emperor invaded and wanted to sacrifice the whole world, but no one could stop it. The disciples watched the world fall into despair in pain.

At this time, Li Xuan appeared and slashed a sword against the Demon Emperor under the watchful eyes of the public.

Boom!

The sky fell apart, the invincible Demon Emperor fell on the spot, and the entire dark world was swept away by a sword.

The disciples were horrified. It turned out that the strongest person in the world was actually the master who had been in seclusion for ten years.

- Description from novelbuddy