One Piece – Thundergod Marine - Chapter 15 Too Much

A data loving young man from Earth has an accident which transports him to a dark land filled with terrifying creatures and magical powers. Fortunately for him, he has a Biological Assistance Chip to ease his path. However, things in this bizarre and strange world are not always as they seem, and, though it is a tremendous asset, the chip doesn’t always work as expected. With all of the crazy creatures and magical mayhem around him, one can only wonder what the future holds for this young man…

- Description from novelupdates

220 years ago, in the legendary Dragon Demon War, Hero Azell ended the war by killing the evil Dragon Demon race’s King Atein. He was able to save the population, but as a consequence, he was cursed. While he was dying, the high magician suggested a gamble that might save his life.

#Expect a big Harem but MC won't mindless collect women on a whim. There's deep mature content. Beware!After getting rejected and humiliated by the very woman he's ever loved—and publicly dumped during lunch break in front of half the school while holding a giant teddy bear, blue roses, and a handwritten love letter titled “My Heart in .mp3”—Jayden Cross thought life couldn't get worse.Then he wakes up with a system talking in his ear.[Ding! Welcome to the Ultimate Copy and Paste System!][Function Unlocked: 10x Copy and Paste!]Now armed with a divine-level Ultimate System Jayden begins rebuilding his life with just copying and pasting everything and gets 10X more!What the world, the system, and the universe had shattered without remorse, only the Ultimate Copy and Paste System could restore. But it did not simply mend—it reimagined. It rewrote his broken existence into a force no storm could contain, only follow.

One god, one faith, one world, one mage… I am the only mage in the world.

- Description from Ptwxz (translated)