Naruto System in One Piece - Chapter 154: The World Noble

The black dragon that rose from the depths of the South Sea unleashed an apocalyptic tsunami... Flame demons destroyed city after city made of steel and concrete, calmly departing from the center of nuclear explosions... Alien gods attempted to rule the entire galaxy...This is a future world where human technology is highly advanced.It is also an era that sparked a frenzy of Life Evolution in the Martial Path.Li Yuan, a Martial Path student on the verge of taking his college entrance exams, struggled to advance in this world while harboring the peculiar Divine Palace capable of envisioning the galaxy.Years later.“My current flying speed is 122,682 meters per second, and my power burst is...” Li Yuan flew at extreme speeds through the atmosphere about 180 kilometers above the surface of Blue Star, his cold eyes fixed on the massive creature at the dark void's edge, resembling the mythological dragon: “You, must be the strongest among all the invading Demigod life forms.”“It's just unfortunate that I can now be called... Martial God!”

Ethan Carter was a failed fantasy author who died overworked and bitter. When he wakes up in the world of his own unfinished novel, he finds himself reborn as Darius Wycliffe, a weak and arrogant noble fated to be killed by the protagonist, Lucien Ashford, the Archmage’s Disciple.But Ethan refuses to die so easily. Armed with his knowledge of the world’s secrets and a unique ability to rewrite spells, he dives into the forbidden magic he once created but never fully explored. As he grows stronger, he uncovers terrifying truths about the world he thought he knew.To survive, Ethan must defy destiny, master the deadliest of magics, and challenge the very hero he once wrote to be unbeatable. But what happens when the lines between hero and villain start to blur?

This is the reupload (at his request) of the chapters previously posted by craftyprogamer as he wants to focus on his own book

Forge unparalleled mechs with the ambition of old age, and use the galaxy as a knife to smash the edge of the empire.

His name is Ji Xinghe. When he was 65 years old, he went to Alien Battlefield to avenge his son.

The old man is standing on the ground, his ambition is a thousand miles away, the old man wears armor, and fights to the galaxy, the old man drags his sword, it is not for glory.

- Description from novelbuddy