PLEASE NO

There is no real or fake Ciel, I believe it was one of the members of the Star group that the tea cup guy was working for

Actually, I believe Vincent had two sons - twins. There are tons of clues that the "real" Ciel was killed right before Sebastian appears and make the contract. At this moment, the weaker twin, which was still alive, choosed to assume Ciel's name - wich, being stronger and older, was the heir of the Phantomhive family (Lizzy also comments that the Ciel who came back was shorter than before). For instance, when Sebantian asks how the little boy wanted to be called, he takes the ring - which was at the finger of the dead kid laying on the table, and answers that he is Ciel Phantomhive. This is only one of many clues given by the flashbacks.
Well, this is a theory in which I strongely believe. And now, I believe that the dead twin is actually alive - but it is only a guess. The reason why I consider it a possiblitity is because Agnil's reaction when he look at the piece of burned photo - in which he would have seen the twins, since it is from when they were kids. Also, there is Soma's reaction when he opens the door.
But it is only a theory, who knows what Yana sensei is planning ╮(￣▽￣)╭

Yes but I did suspect that Ciel had a twin, but if Ciel had a twin I wonder why Agnil reacted the way he did, wouldn't he have be like "oh cel has a twin!" and how did he relate this picture to his master being in danger. He didn't even know Ciel had a twin. But I do agree that Ciel might have a twin since in a chapter it show him in a cage saying to someone "As long as I have you, its okay" or something like this. But right now I want to know who killed Agnil and attack his master( don't remember his name), and it had to be someone they both knew. Also, his master would have normally reacted with a big smile and red chicks like always...IDK everything is really confusing...there is also the fact that Undertaker made Ciel drink something...

change the name "master" to Soma I just saw that you were saying his name.
Well to add, whoever is this "Ciel" I will always be at his side, even if the whole world is against him, including his twin.

@Nishi, after the last chapter, don't you think my theory can be right? ヾ(❀╹◡╹)ﾉ~

Yes..I do know, this is what I needed. But whoever is this person that call himself Ciel I will stay on his side.