Devil And Devil. The ongoing battle between good and evil, both angel and devil, is still going on and none of them wants to give up. The tale is about Sword, a demon who has a rival angel named Io. They fail to the point where, in their 101st battle, they badly wounded each other, and both fell toward Earth. Having deep wounds but not wanting to die, Sword is looking to own a body. He found a bit of a detailed, beat-up, unconscious boy so he went into it and allowed him to live.