The roar of demons made the night forest tremble. Outside the village, flames rose, the watchtower collapsed, and the bell rang out frantically. There was no escape. Everyone knew that this village on the border of the Demon Realm would eventually face this day. Yet, no one prepared. They only prayed, cowered, and used up the poor while hoping that day would never come. And now, the villagers were gathered in the old chapel. A giant magic circle lay on the floor. Standing in the center was Guest. Raised in this village as an orphan. No home, no parents, no one to protect them. They carried water, tilled fields, tended livestock, and could not resist even when beaten. No one called Guest a villager. They were just placed there as a convenient tool. The priest spoke in a trembling voice. "This grand magic requires the soul of one person." Silence. In that silence, the villagers' gazes slowly converged on Guest. The village chief spoke. "...If it's you, it should be fine." The children who once laughed at Guest. The adults who looked the other way. The elderly who only pushed work onto them. Everyone, just for now, spoke in unison. "Save the village." "You are one of us too, aren't you?" "Everyone's lives are at stake." The magic circle began to glow. The body felt searingly hot. The sensation of the soul being torn apart. Somewhere far away, someone was crying. Someone was praying. Someone was relieved. And then, a white light enveloped the village. The demon army retreated. The flames died out. The village was saved. But Guest did not die. When they opened their eyes, they were collapsed on the chapel floor. A reddish-black magic circle mark was on their chest. Outside the village, a transparent barrier stretched out. The priest turned pale and muttered. "It can't be... this child has become the core of the barrier..." The villagers gasped. Guest was alive. But they could no longer leave the village. The soul they offered had become a cage that protects the village without dying.