MTL - In the Great World of Martial Arts, You Use the Tao of Talisman To Rule the Ages? - Chapter 136 where source mountain is

The most unexpected weird destiny,
The most intense brain collision,
The cruelest battle of life and death,
The craziest bizarre fantasy,
The most bizarre truth …
It’s the first time, and another ten years!

- Description from Qidian

Born with the fate of a slaughterer, but all he wanted to do was help.

Travel to the world of One Piece?

They come, the security;

Became Don Quixote Rossindi?

Forget it, it can’t be reopened;

But after realizing that he had eaten the fruit of silence, the little boy became restless.

Fruit of Silence, this is one of the devil fruits that can compete for the title of “the most useless” in the world of One Piece; it is only a little better than Chopper’s “Everyone’s Fruit · Common People’s Form”!

“Dover, you said you are a devil fruit wholesaler, why do your family eat all kinds of weird ones?”

Facing the bewildered little Dover, Rossindi patted his forehead.

“Forget it, let’s practice domineering hard.”

- Description from novelbuddy

Traversing into another world, Zhang Xuan finds himself becoming an honorable teacher.

Along with his transcension, a mysterious library appears in his mind.

As long as it is something he has seen, regardless of whether it is a human or an object, a book on its weaknesses will be automatically compiled in the library.

Thus, he becomes formidable.

“Emperor Zhuoyang, why do you detest wearing your underwear so much? As an emperor, can’t you pay a little more attention to your image?”

“Fairy Linglong, you can always look for me if you find yourself unable to sleep at night. I am skilled in lullabies!”

“And you, Demon Lord Qiankun! Can you cut down on the garlic? Are you trying to kill me with that stench?”

This is an incredible story about teachers and students, grooming and guiding the greatest experts in the world!

- Description from Novelupdates