Flash Marriage: The Prince's Contract Wife - Chapter 383

A cauldron, a secret forging method, and his blood created an ultimate weapon. The youngest Sword Crafting Master on Earth had been reborn from another world. With the Nine Yang Divine Furnace and a scroll of Divine Equipment, he was like a fish in water, standing at the pinnacle of the martial way. There were tens of thousands of clans, billions of cities, and countless experts. He was the master of ups and downs!

Though it felt a little awkward to be my good brother’s aunt, it was really exciting to find out how handsome and rich his uncle was.

- Description from Novelupdates

This is a world where humans, demons and mysterious beasts coexist.

Humans cultivate mysterious qi. Demons cultivate corporeal bodies. Mysterious beasts cultivate soul perception.

A legend says that in the middle of an endless rainforest, there are extremely powerful existences; they are called demon kings.

Some demon kings have a tyrannical corporeal body, some are experts in illusions.
Some demon kings are proficient in magic, some can even move mountains.
Some demon kings are able to sense things thousands of miles away.

These demon kings rarely appear in the human world. Even if they emerge in the human world, they would reincarnate in human form; assimilating with mankind while seeking to breakthrough realms…

- Description from Novelupdates

Bai Yu traveled to the world of One Piece and activated the strongest swordsman system at the beginning.

No need to practice, swinging a knife will become stronger!

Thus, Bai Yu started his daily routine of wielding a knife.

Swing the knife 1000 times, and get the limit of physical strength – six styles.

Swing the knife 2,000 times to obtain the powerful Qinglong Sword Intent.

Swing the knife 3000 times, get three-color domineering.

General Huang Yuan: Bai Yu is the strongest rookie I have ever seen.

General Aokiji: My freezing ability was directly chopped into pieces by Bai Yu!

General Red Dog: Dangerous! My marshal position is about to change!

Hawkeye: Bai Yu is the number one swordsman in the world!

Since then, the name of Bai Yu has resounded throughout the world of pirates.

- Description from novelbuddy