Kono Sekai ga Game dato Hanmei Shite 100-nen ga Sugita: Project venturum saeculum (Volume)

is the first volume of the Kono Sekai ga Game dato Hanmei Shite 100-nen ga Sugita light novel series, written by Ki Mizu and Illustrated by Pisuke. It was released under the Dengeki Bunko Imprint in July 2018.

Synopsis
A world where 100 years have passed since we knew we were the inhabitants of the game. Even the meaning of adventure has become a mere "custom". Heading to the coming-of-age ritual "First Quest," Migia faces an unprecedented situation that could never have happened in this world. It was Zeku, a level 1 swordsman who boasts tremendous sword skills, who saved that predicament. Who is this boy who calls himself a player? And what is the mystery hidden in this world that he is trying to unravel? With the first player in 100 years, the closed game world will change !?

(source: Dengeki Bunko Website)