Reincarnator

Humanity was dragged into the Abyss by a bored god to battle monsters and rival races. They lost. In a final, desperate gamble, the last survivors sent a single comrade hurtling back through time. Armed with future knowledge and a burning second chance, he must rewrite history before the Abyss devours everything. No gods, no monsters, and no failure—just one man racing against fate to save a doomed species.