Naruto System in One Piece - Chapter 23

System: You are now a lowly male supporting role, a passerby who wants to go offline at any time, please keep secretly and grow vulgarly.
Shi Yan: Very good, thank you for your suggestion.
The first world: Shi Yan, as a little prince born in a cold palace, made himself an emperor.
The original male and female protagonists, under his witness, became grudge couples.
The second world: Shi Yan, as the youngest son of the princess who died tragically, made himself a powerful minister over ten thousand people.
The original male and female protagonists, under his witness, became grudge couples.
The nth world: Shi Yan, as a genius in the world of comprehension, has made himself the number one powerhouse in the Three Realms.
The original male and female protagonists, under his witness, became grudge couples.
The system feels that something is wrong.
Shi Yan instead persuaded him: Let the male and female protagonists come together in the end no matter what the circumstances are, isn’t it the self-cultivation of the tool man and the male partner?

Content tags: Kuaichuan Shuangwen Metaphysics
Search keywords: Protagonist: Shi Yan ┃ Supporting role: ┃ Others:
One sentence introduction: The male partner is beautiful alone
Purpose: strong heart, unmoved by wind and rain

- Description from novelbuddy

What if you could hack the strongest heroes and turn them into your devoted companions?Once feared as the Heavenly Demon, Zain stood above all—unstoppable, unrivaled, unchallenged.But his reign came to an end when so-called righteous cultivators banded together to eliminate him, believing they had purged the world of its greatest evil.Yet death was not the end.Reborn in a world dominated by heroes and champions of justice, Zain awakens a mysterious Hero Hack System—a power that doesn’t just defeat heroes but rewrites them.With a single command, he can shatter their convictions, twist their destinies, and rebuild them into something new.A ruthless warrior queen? Now a loyal blade at his side.An untouchable holy maiden? Now eager to obey.The strongest hero who once stood against him? Now kneeling before him, waiting for his command.With every hero he hacks, his harem of once-unshakable warriors grows. But as he reshapes this world to his will, one question remains—who gave him this system, and what price will he have to pay?They ended his reign once. This time, he’ll reign over them all.

I thought being laid off from my job was the greatest of my worries but I just had to wake up in a ship's cockpit after my space game crashed. Now I have no map, no friends and no money.But that's ok, I've started from the bottom before! With my starter ship I will scour through space as a Mercenary and maybe even start up a Mercenary Company while I'm at it! This ain't my first rodeo in space after all!Except... Apparently my crew members are weird?The guy who bumped into me yesterday was found sliced up and floating outside the space station.The girl who tried to honeytrap me was reported missing with only a finger found in an alley.And then that merchant who scammed me had his entire ship blasted into bits by unknown vessels the very next day.Some people say my crewmates were behind it but they must be mistaken, right?I only know one thing for sure...In space, no one can hear you scream...

Wu Lai was an ordinary high school student. One day he was struck by a flash of lightning from a different world, and suddenly entered a fantastic world full of magic and swords. Since then, he started a totally new life. In this supernatural world, he had his ups and downs, experienced numerous battles, subdued powerful evil beasts, and fell in love with a belle. His nickname “Demon King” was remembered throughout the ages there.

Stay or return was a question. In the face of this choice, Wu Lai, with the nostalgia and gratefulness for the original world, finally chose to stay…

Here was the legend of “Demon King”…

- Description from Novelupdates