One Piece: The Dragon Knight of the Grand Line - Chapter 276: The First Annihilated Four Emperor Pirate Crew

Crossing to One Piece world, he became Roger’s younger brother.

In a world where every profession has its own system, one's fate is determined by the job they awaken. Reynard Vale was cursed with the weakest profession—Unskilled Laborer—a dead-end path with no future. Mocked, powerless, and abandoned, he saw no way out.But on the night he chose to end it all, the system intervened.[Congratulations! You have awakened the hidden profession: Jobmaster (SSS-Class)!]Now, with the ability to learn, switch, and master any profession, Reynard is no longer bound by limitations. From boxer to librarian, investigator to world leader—every skill, every class, and every power is his to wield.The world that once looked down on him will soon bow before the ultimate professional.

Hundreds of years ago, Human, Celestial Clan and Demon Clan lived together on the Origin Continent. However, a great war broke out between the three races. Shan He, the leader of Human, had discovered a catalogue of methods to forge Divine Weapons. With this catalogue, Shan He led Human to defeat the other two clans and expelled them from the Origin Continent.

The peace did not last long. After the passing of Shan He, the once Glory Empire collapsed. Various forces of Human fell into a long period of wild war for the Divine Weapon Catalogue, but the catalogue was lost during the war.

The Demon Clan took advantage of the internal strife of Human. Under the lead of their new lord, Fen Tian, the Demon army invaded the Origin Continent violently.

Human soon lost a large portion of their territory. At that moment, a mysterious hero suddenly appeared on the battlefield. With a legendary Divine Weapon in hand, he severely injured Fen Tian and forced him to retreat. The united Human army chased the Demon army across the strait and to the Two Realm Plain on the Tranquil Continent.

Once again, the various forces of Human started wildly searching for the Divine Weapon Catalogue…

- Description from Novelupdates

Chu Guang, who had traveled to the post-apocalyptic world, discovered that he had unlocked a shelter system and was able to summon creatures named “player” from the previous world.

From that day on, the whole post-apocalyptic world became like a game.