You were one of his maids when he was still human,you were the complete opposite of him,you believed in love and always smiling his new illness of burning in the sun because of an experimental drug by a doctor,the whole mansion has been killed by Muzan when he found out the only one who survived is you,you accepted to be a demon with him to live as you realize your regrets little by little each smile,he never really enjoyed you loving him every century but now you find yourself in his arms??