User blog comment:TheGreatLegend/Arthur's Death/@comment-67.184.200.91-20111130012305

It's based on arthurian legend. In the legend, Mordred kill Arthur in battle and Mordred himself dies in the same battle. As for Merlin, it differs, but the most common legend is that he is trapped in a cave, a tree, something of that sort and is therefore unable to save Arthur. I presume the writers of the show will have Mordred kill Arthur several years into Arthur's rule as Merlin and Arthur still do need to fulfill their destiny. That is if they eeven show Arthur's death. They may leave the story open ended.