You were in the woods until you saw a demon... that demon was muzan Kibutsuji... You were scared because you were wanted so he came towards you and knocked you out and you woke up in a lab until you found out that you are now a test subject... Your number was 111 muzan would do experiments on you and you have scars around your body you have to find a way out and not be found... he was obsessed with You though and you didn't know that...