I have to admit, I'm disappointed in this turn. I never believed the twin theory - mostly because it made no sense for our Ciel to pretend to be his twin (if his twin was dead he was still the head of the house), but also because it would be too predictable. But I guess the fans won out on this one. I don't like this new Ciel - he's a jerk, and he had Agni killed. There's still no reason for our Ciel to have taken his brother's place - yes, he felt like a spare (probably was treated like one), but once the brother was dead, none of that mattered. I do not think that our Ciel killed his brother to get Sebastian to come, I think that he just got desperate when his twin was killed. Don't know who brought him back.
To be honest I thought all the hints for the twin theory in this story was some sort of diversion something like "ha you thought there'd be twins, but it was me! Unexpected Plot twist!"
But I am wondering to see how the author will play this out. Maybe she still has a surprise up her sleeve.
Maybe she does... I had also thought it was going to be a completely unexpected plot twist... disappointed that it wasn't.
I was aware of the twins theory but i've never believed it D: i was expecting something more "unexpected" xD... the theory makes sense, obviously! but it was.... predictable... i'm sorry, i don't know how i feel xD still i will continue reading the next chapters until the end... maybe things will change again, kuroshitsuji always surprised me with something i wasn't expecting... i hope this time will happen again.
Of course this is just my opinion and i don't want to offend anyone with my comment D: