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

Hmm, no I don't agree actually; "I thought you were my sister" wouldn't have had the same impact as "friends", because brothers and sisters are not necessarily close/affectionate/on the same side whereas 'friends' is about a bond you make willingly with someone, and it's always positive. Also, she is still his sister, so it wouldn't actually make sense to say "I thought you were my sister" because she can never stop being that. Whereas she has (largely) stopped being his friend.

And moreover, Arthur DIDN'T think she was his sister for most of his life, he thought they were friends, probably best friends at some point. He'd probably still think the idea of her being his sister is deeply disturbing and weird (I do anyway), because he's grown up with her as a friend and a companion not a blood relative.

But I did wonder about Arthur never referring to her as a sister. I think they both find the idea quite unpleasant - Morgana is very very bitter and sarcastic when she calls him brother, while Arthur avoids it altogether. He also says "can't blame me for MY father's sins" as opposed to our, which kind of implies some kind of refusal to consider themselves siblings.

I personally hate the sibling thing anyway, and I hope it gets underplayed because it was a clunky plot point they shoved in too late for me to accept. I do hope there's more Arthur/Morgana confrontation next series and my ideal would be for them to somehow end up in a grudging alliance against a common enemy. Slim though that hope is ;D