One Shot

One shot, just one. That's all they get. One shot at surviving. In this world, there's only one rule, survive. There are no gods or holy beings, no demons either. Only people. A world created separate from the rest of reality, the author created this world and let it develop on its own as an experiment to see what would happen if he removed all powerful beings from esistince on an attempt to end a war he knew would inevitably come. The results were... questionable at best. Without gods or demons, the world lacked any mana, any magical energy to hold it together. Every fifty years, it comes apart and rebuilds itself. The author, after seeing it, had given up on the world and left it to focus on preparing for the inevitable war. Now, those born into this world have one shot, one shot to stop the world from ending. However, there is one consistently, a young warrior, who on the last day, remembers his past lives. One shot, that's all he has, or everyone dies and it restarts. One more go?