Poetry, Sword and Zen

Master said: Monks do not kill. Then the master died and the temple burned down. Sixteen-year-old monk Liao Chen went down the mountain with a blunt sword on his back. When he saw the mountain of corpses, he broke into the thicket of swords and killed someone. He still doesn't know how to chant sutras and achieve salvation. He only knows three swords. Cutting off karma and breaking obstacles, the last sword has no name. Master said it was reserved for "those who deserve to be killed". I have traveled a thousand miles away from the dust and still haven't figured it out—— Who is the one who deserves to be killed?