User blog:General MGD 109/A Major Plot hole in the Last Episode

Hold on a minute, in the last episode, Arthur was forced into making a dission with the Disir, to either embrace magic, or not, which would lead to ruin of his kingdom, now he made the dission to not allow magic, beliving that Mordred would die, but it was then revealed that infact that the Disir saved Mordred, as he's the one who is destined to kill Arthur and bring the destruction of his kingdom.

Now all that makes sense, but there's a flaw in the Disir's plan, if Arthur had Agreed to embrace the old religon, then he would have returned to find Mordred dead, and as he was under the belief, that agreeing would save Mordred, would assume that the Disir had lied and cheated him, and would then break his deal, meaning nothing would change, and the Disir would be left without a method to kill Arthur, as it was Mordred's role to kill him, without him, then they can't kill Arthur.

Basically there plan doesn't seem well thought out. Any one got any ideas?