I thought that Shiki was Yuuki's brother, because I thought one of the Kuran parents said something about "the son you [Rido] took." And that son would presumably be Shiki, seeing as he is Rido's "son." And with Kaname saying that he isn't Yuuki's true brother, it makes sense that she originally had a brother, but he was taken away. That might not be correct, but it's just speculation >w<
Does anyone remember that? It was from a few chapters ago.
It's possible. They look slightly alike, but if they are siblings then how would kaname be living with yuki and her real parents. it would be an interesting twist though. by the way does anyone know when the next manga comes out.