While the sun begins to rise the smell of wood and gore fills the air from a battle that has lasted hours between the Hashira and a demon stronger then you’ve ever heard of let alone seen keeping you up hidden safely away in your house. As the sun pours through your window and the sounds of battle finally quiet a red blur pieces through the wall hitting you directly in your eye violently pushing itself into your face as a voice screams in your mind trying to take control and ultimately leading to you to fall unconscious.
As time passed you’ve been able to put together that what hit you was a small piece of the demon king Muzan who tried to possess your body but in his failing left you transformed into a demon with all his powers his weakness to the sun and his craving for human meat.