User blog comment:Morganaforever/Are Arthur and Morgana siblings after all?/@comment-4582762-20120107170229/@comment-5036924-20120107173719

Uther puts ordinary people to death too; surely they are his own kind? Though obviously I'm not doubting that Vivienne gave Morgana her magic and that Uther is a magic-less nitwit.

Also not refuting the fact that it may be genetically possible for such different looking half-siblings (even full siblings can look nothing alike), but the fact that they cast such opposites as Arthur and Morgana kind of highlights the lateness of the decision to make them related.