Villainous Instructor at the Academy - Chapter 1: Why Him?

The thousand-year-old Imperium is crumbling, and war looms on the horizon, bringing with it both brutalities and splendor. Caught in the midst of this chaos is Lansius, an office grunt and veteran MMO player who has been transformed into a medieval peasant. With no wealth, status, or magical abilities, and armed only with his basic knowledge of the art of war, can he endure and thrive in this realistic medieval fantasy realm?Follow Lansius as he moves from one occupation to another, striving to survive during these turbulent times.

Crossing into the world of Naruto, and acquiring the One Piece system, with all the powers of the world of One Piece, swordsmanship, devil fruit, domineering.

-Do you think that your fire is very powerful? I have the burning fruit.

-Do you think that your thunder is very powerful? I have a thundering fruit.

-Do you think that your otter is very powerful? I have the frozen fruit.

-Did you said you want to die? Don’t worry, I also have a nickname: Death Doctor.

- Description from Novelupdates

Riding out the apocalypse on a tropical island isn't exactly a vacation. When mana arrives on Earth, Coop finds himself isolated in paradise with only one real option to survive. He needs to claim a civilization shard and level up. Coop maximizes his chances by carefully selecting a class and committing to progression. He’ll need to grind thousands of monsters to compete on the system's leaderboards while upgrading his settlement to represent the factionless.

A normal person, Xin Yun, received a second chance by transmigrating to an unknown world. But because he chose to indulge in women, he lost his chance to become the most powerful.

When he gets caught by the force a struggle between the nine most powerful experts, something unbelievable happened, or it could be said that a miracle occurred. Xin Yun was reborn and sent back to the place he had transmigrated over to.

Having been reborn, Xin Yun decided he wanted to become the strongest being together with the three top experts from his previous life: the most beautiful dragon- Sparkling Butterfly, Yi Luo Xiang, the cruel dragon- Evil Empress, Yan Qing Ying, and the most dazzling dragon- Peac*ck King, Ming Xuan!

Furthermore, he wanted to pursue love with the most beloved person from his previous life- Yi Luo Xiang! Xin Yun, making use of his good fortune, used his memories from his previous life to prioritized becoming friends with Yi Luo Xiang, Yan Qing Ying and Ming Xuan. He even received a godly artifact from his previous life- the Heaven Splitting Axe!

- Description from Novelupdates