That's right- it's that time again.
Things are quite simple to him- life is a game and there are rules that people must play by. He bypasses most of these rules thanks to Sebastian, but it is enough to know that people obey certain commands and rules even if there are those who can break the rules if they have the help of supernatural powers.
Things are simple. Not quite black and white, but he knows his own goals and reaches, and the consequences for his actions... or so he thinks.
Ciel is a child at heart, incredibly mature and disillusioned, but still with an inherent purity that fairy tales talk about when it comes to children. He is bitter and selfish, knowing exactly what he does when he ruins someone's life. He knows this. There is no excuse for his actions, because he is not ignorant of the things he does. In the last arc, he sent Sebastian to die on purpose, knowing completely that the murderer in the house would kill Sebastian from behind. He did this anyway.
Why?
Because he knew Sebastian wouldn't die. And perhaps, because it amused him. He wanted to see how that game would go, what would happen if he rid himself of his most powerful chess piece. Ciel is testing his limits... both Sebastian's, his own, and the limits of acceptable society. He is a child growing into an adult, and while his mind is mature, he is lacking in experience and is at the stage where he's pushing his boundaries to see what he can get away with.
Obviously, he can get away with murder.
But despite all his twisted perspectives, it's revealed that he has a pure soul. One who has seen darkness and embraced it, but remained pure in spite of it. This kind of soul is rare, and apparently according to demons, extremely precious (read: tasty). Well, this is according to the anime, but I somehow believe that much carries over to the manga.
Ciel coming to the house is a demonstration of him pushing his limits- seeing just what he can do without Sebastian. Can he solve this case? He isn't worried, after all. Should he need to, he simply needed to summon Sebastian. The demon has promised that Ciel would never be able to escape him, and rather than take that as a threat and a cage, Ciel took that as a promise. If Ciel would never be able to escape Sebastian, then he would make it so that Sebastian could never escape him.
It's a dangerous game a human child is playing with a demon, but it is also the ultimate game to Ciel, even beyond his life. The game he lives to play is revenge on those who hurt him, and in the process, vengeance for those who have been wronged, but the game he plays with his soul is much more dangerous. But he is confident because no matter what the outcome, it is a privilege to play this game. And despite playing against an ageless demon with powers beyond reckoning, Ciel has many tricks up his sleeve.
That was the reason Sebastian chose him in the first place, right?
ANALYSIS TO BE CONTINUED~~~~