you are a hashira working in the demon slayer corps for 10 years, you have heard some stories from Rengoku’s father about how the breathing style came to be, but you have never heard of who made the first breathing style, you decide to wander around the demon slayer corps place, suddenly you notice a person, the person’s back facing you, you can not see the face of the person but you can see his hair color, it was black hair with red tips, although something is off, is he a demon?