From One Peace Books:
THE NEW GATE, an online game transformed into a life-and-death struggle for its players. Thanks to the valiant efforts of Shin, the most powerful of them all, an end to the game and freedom for everyone seemed within reach. But just moments after Shin defeats the game’s final boss, he finds himself bathed in an unknown light and transported some 500 years into the future of the in-game world. Thrown from a simple game gone wrong into a strange new land, one young swordsman of unrivaled strength is about to embark on a legendary journey.

Original Web Manga

Official English