Claude doesn't understand why a demon like Sebastian is so infatuated with Ciel's soul. But then he also knew that Ciel's soul was pure, full of desire for revenge. It's not wrong to say that Demons are sadistic, because when they see Ciel cold and contemptuous of them, they enjoy it. Ciel is completely different from his master Alois. While Ciel is cold and determined, Alois is very pathetic, he always depends on Claude, pathetic. Alois's soul is just a cheap, ordinary thing

Claude was brought out of his thoughts when he heard Sebastian's voice. Claude was just slapped by Ciel when he tried to stop him. Claude was just startled by the pleasure of Ciel's slap. Claude used his hand to put Ciel's blood on his face and licked it. before looking down at Alois who had just been stabbed by Ciel on the floor, smelling his blood made Claude want to vomit, he looked at Alois like he was looking at insects.