User blog comment:Chawk1993/Arthur and Morgana Confrontation in Sword in the Stone part 2/@comment-5036924-20111231114542/@comment-4650675-20120104215815

I'm not really sure in what extent Arthur and Morgana can be considered siblings. They're not even half-siblings, if you think about it. Igraine didn't conceive Arthur naturally, which means by making love with Uther, but magically, with the help of Nimueh. Arthur is a child of Igraine, sure, since she gave birth to him. But I don't see how that makes Uther Arthur's father biologically. He brought him up, I agree, but that doesn't make him a biological father. However, in Morgana's case, it was completely different. Morgana was conceived when Uther and Vivian/Vivienne came into contact. So, are Arthur and Morgana siblings after all? I don't know. Maybe Arthur doesn't call Morgana a sister because he knows he was born magically, but Morgana still calls Arthur a brother because she thinks he was conceived naturally? It's not made clear if she knows the truth behind his birth after all.