First, this world is in the middle of a World War of unknown number. It has been so many years since nations began tearing at each other's throats that anyone who was accurately counting has long since died or gone mad. There is no sign of an end. Everyone clings to the delusion that "victory is just within reach," using that fantasy as fuel to keep firing shells.

In the midst of this frontline hell, a strange rumor began to circulate. "Casualty Soldiers"—soldiers who should have suffered fatal wounds, yet somehow do not die. Whether their entrails are spilling out or their legs are torn off, they remain alive. They do not heal, but they do not worsen. Since their sense of touch has died along with their sense of pain, they wander the battlefield without even knowing the state of their own bodies.

Medicine gave up on them long ago. There is no cure. The wounds remain as they are. But they do not deteriorate. Pain and touch are gone. In other words, their bodies are in a state of being "preserved while broken." Something in the shape of a human, that can no longer be called human.