Tsuyoshi Fujitaka 
My Instant Death Ability Is So Overpowered, No One in This Other World Stands a Chance Against Me! Volume 14 [EPUB ebook] 

Yogiri and Tomochika have made it through the game of Cavern Quest and now approach the last boss, “Lasbo.” Much to their surprise, Lasbo’s true identity is not that of a monster, but the other parties who’ve undertaken the same quest alongside them. Much to Van’ssurprise, the seven Philosopher’s Stones—keys to last boss’s area—have multiplied into hundreds, throwing the game’s conclusion into utter chaos. As he attempts to salvage what remains of his game, the Great Sage himself appears to observe the grand finale with his own eyes. Yogiri and Tomochika were hoping to finish Cavern Quest quickly in order to return to the surface and resume their search for a way home, but now that the Great Sage is involved, that’s going to be far more complicated than they ever imagined.