User blog comment:GWAINE/Finale Speculations...?/@comment-5788405-20121204201159

I don't know about what the producers have planned but for me, I think that Arthur will receive a fatal wound and to save him Merlin will sacrifice his life (to create a life another life has to be taken - balance maintained).

That will make Arthur realise the worth of Magic.

Morgana and Mordred will die.

As far as the knights are concerned they will die too.