In a world with Gates and monsters but no hunters, I survived for 32 years using only technology. Destruction, then regression. 32 years into the past. Human Survival System, Savior. Reality finally transformed into a game-like world, befitting a hunter story. "T-that's a gun...?! Don't you know the basic fact that guns don't work on monsters because of their mana barriers?!!" Hmm, that's not true. My gun penetrates both mana and barriers. Tsk, these young people nowadays. They think the whole world works like a game?