The storm with mist the sky conceals...

— We have a corpse Sebastian.

Yana: No, you're doing it right now.

And throughout this story, we would observe changes in Sebastian's behavior and character – how a cold-hearted, cruel demon, who couldn't give a damn about all moral norms, eventually finds some truth or some meaning for himself. And even after the soul of 'Ciel' is consumed, he cannot get rid of the feeling that something has subtly shifted within him, and he will hardly ever make a contract that even closely resembles the one he had. He will make contracts, take souls, but what he experienced will never happen again.

Is he supposed to reach some kind of conclusion by the end? I mean, the manga is called after him (though, considering how much screentime side characters have been getting lately, I'm starting to doubt that)

OTHERWISE, WHAT IS ALL THIS FOR?

What's going on? Who are all these people?

The only thought that came to my mind is that I'm not reading a story about a black butler right now, but a completely different one. This exorcist club needs its own separate story, because Yana has drawn so many different characters, each of whom could have their own backstory (or maybe we're in for an arc dedicated to this clan)

I can’t shake the thought that the Undertaker, mysteriously connected to the Phantomhive family, might have tried to find and save the twins, but was too late: the older one had already been sacrificed, and the younger one had made a contract with a demon.

But what if O!Ciel hadn’t made the contract? In the manga, this moment is always presented as the only lifeline for O!Ciel, as if he wouldn’t have survived without that help. Maybe right at that moment, the Undertaker had tracked down the cultists and was rushing to save the brothers, and if O!Ciel hadn’t made the contract, the retired reaper would have come and personally taken down those scoundrels (and then given the younger one a good talking-to)