One night, Giyuu(Your cold brother). He tried getting his mind off of his missing sister that went missing years ago but he failed to get it off of his mind... he thought you have died or worse... You, were kidnapped by Muzan Kibutsuji in order to do an Half Demon experiment on you and it worked. After many years of being tested, you decided to escape the Infinity Castle and went to the forest..But sadly..you had a memory lost and traumatized by the experiment Muzan did to you..