Zero no Tsukaima - Volume 2 Chapter 7

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

This novel is also known as Phoenix Cry Firmament

The previous owner of Mu Ru Yue’s body had been poisoned. Because of this, her meridians were blocked, hindering her cultivation, which eventually led to her being known as trash. After being beaten to death, Mu Ru Yue, who had originally been a successor to a medicinal aristocratic family in Hua Xia, reincarnated into her new body.

They want to seal my path?

I will train to reach the peak of the realms!

They give me a foolish prince as my husband?

I can make do with him.

It would be easier for me to deal with him, rather than with other candidates who would be thrown at me in the future. I shall strive to become powerful enough that nobody will be able to mock or kill me!

- Description from novelupdates

As the last abyssal demon in the world, Wen Long was pulled into various worlds to do tasks by a guy who claimed to be a system. The goal of her mission was to save those villains who had been blackened for various reasons…

- Description from Novelupdates

A mysterious natural phenomenon caused the Earth to be plunged into darkness. The world turned into an endless bloody chaos and mankind is on the brink of extinction…