Harry Potter: Eclipse. - Chapter 19:

Shen Zhixian transmigrated into a book as a cannon fodder master who hatefully severed his disciple’s spirit root. This disciple fell into the devil’s path and returned to make mincemeat out of him.

Shen Zhixian just happened to transmigrate into the last moment of the master’s captivity, and then he was reborn again.

After rebirth, he devoted himself to fostering and supporting his disciple, only to discover later that his disciple was also reborn.

Even worse, the disciple still retained the memory of his life before rebirth.

Shen Zhixian: …Disturbed.

Afterward, he realized one truth: Being a master is a high-risk occupation. Not trivial at all!

- Description from Novelupdates

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

An ordinary young man on earth, Xia Feng, traveled to a world of sword and magic, and took the body of Lucien Evans, another ordinary young man.

Seemingly this was a world of traditional western fantasy, yet he discovered the astonishing similarities between the earth and this world, and between science and the so-called arcane magic…

“Knowledge is power”? Soul, magic, quantum, Theory of Relativity, cognitive world, music and real world……

What was the true nature of that world?

- Description from Novelupdates

First World : CampioneCurrent - Second World: High School DxDThird World: ???Reincarnated into the world of Campione! Haru Kasugano, our hero slays gods and ascends as the mightiest Godslayer. He battles powerful God-Kings and Campiones, claiming victory after victory. Whatever it is. [Wealth, Power, Beauty] he has it All. Watch him grow stronger as he travels into new realms like High School DxD and the Fateverse, leaving a trail of defeated gods and captivated hearts in his wake.