A thousand years have passed, yet I still regret that day. A thousand years have passed, since that fateful day. A thousand years ago when the world was still young, A thousand years ago when the Sun shone so bright, A thousand years ago when the world was filled with light, A thousand years ago, a demon was born. Muzan Backstory Fanfiction I do not own the fan art. I do not own Demon slayer. But I do own my storyline.