"THE NEW GATE", an online game that had turned into a death game, was now releasing the tens of thousands of players that had been dragged into it, thanks to the efforts of Shin, one of the oldest players. But after he had defeated the last boss and freed everyone, he was swallowed up by a strange light and found himself inside the game world 500 years in the future.

adaptation of the web novel of the same name

Original raw:
http://www.alphapolis.co.jp/manga/viewOpening/428000082/