[ It's a true pleasure to watch the blood drain from Ciel's face in horror, but in manners, Sebastian is still his butler, so he reaches into his pocket to pull out the handkerchief he always keeps there, which he offers to Ciel. His voice is gentle, as if consoling him, but like the action, it's at odds with the pleased and content smile on his face. ]

Not for humans, no. But demons are revolting, are they not? Of course we would keep such creatures just as you would keep a dog.

[ His smile is knowing, because there's a clear double meaning in his words that he wouldn't dare to say more directly. Sebastian doesn't particularly care about the matter at all, but he knows that Ciel would be displeased by the parallel Sebastian is drawing here, since keeping a demon for the sake of Ciel's goals is a knife that he likes to twist when he can. ]