One said that emilia fox is not returning to merlin as she said in an interview that she will be doing another tv season(probertly silent witness).
But this is not true as we have seen pictures of her filming season 4 with katie.
I also founds out that Nimueh, Morderid and alvar will be returing,along with lady vivian and Elaina.
They are also going to introduse more knights of the round table yay.