Dark Swordsman

On the battlefield outside the territory, countless humans use their lives to protect those who do not know the truth of this world. In order to fight against the monsters, they exchange part of their bodies for the bodies of the monsters. Countless extraordinary people come one after another, just to protect human beings. This is the overlap of two worlds. Countless strange creatures called monsters have descended on this world. This is the best of times. We can finally gain power beyond ordinary humans. This is the worst of times. Humanity is barely surviving.