Rebel's Blade
Being abandoned before, K, a simple human, now tries to be a loner. Yet society loves him and cares about him. But his little world gets crushed by the intergalactic advanced alien species, namely Dramons, who, by his sheer bad luck, become his biggest enemy. Being overwhelmingly weak, as a human, he needs to rely on an ancient sword, to fight against this big of an enemy and win, or else, the lives at stake would just perish.
But while doing all that, he gets to learn about secrets he shouldn't have.