I Became a Cannon-Fodder, So I Made My Five Stunning Sisters Divine

I transmigrated into an apocalypse novel after reading only three chapters, and found out that my three goddess older sisters and two childhood friends were about to die protecting a useless cannon-fodder like me? Su Chen panicked. Luckily, there was still a way out: the external trading System had bound itself to him! While everyone else was fighting over a single loaf of bread, Su Chen had already traded gold for genetic potions and equipped his fiery-tempered third sister with a high-frequency blade. While other teams were busy reinforcing their shabby shelters, Su Chen had bought magic tower blueprints with plane currency and turned his villa into an apocalypse fortress. Wait... Big Sis, don't look at me like that! I really only wanted to keep you all alive! And you two, why does this apocalypse feel more and more wrong?