Tanjiro who has become a demon by accident starts his journey with his little sister nezuko. It's not just a role swap au ,it's something more!! What if Tanjiro has been overpowered and mastered total concentration constant breathing since he was 8 years old? What if Yoriichi was the ancestor of tanjiro Kamado? What if the drug to turn a demon into a human was already made? And what if their brother Takeo was still alive? Read out to find out.. The cover and the other pictures does not belong to me......