Tainted Vengeance: World Eaters

Heroes were summoned, wars ended, and the world was saved. Except, it wasn't. The heroes turned traitors and started conquering the world instead. They conquered, destroyed, and ravaged for fun. Meanwhile, a remote village got wiped overnight, with only one survivor. Now surviving the tragedy of his village, Flint, pledges to seek vengeance against whoever dared to unalive all his precious family. * ** *** Ps. MC does eventually get a system but only later on. Pps. There's actual romance in this and MC's only interested in one girl