The new
Merlin magazine has details about a villain and additional details about the roles of previously revealed guest stars.
Maureen Carr will play a villain called the Dochraid, and you can see her in costume on
this page of the magazine, with the blurb: "Check out our exclusive first look at one of the scariest baddies in the new series -- The Dochraid! Played by Maureen Carr, this gruesome ghoul lives amongst all the smelly rubbish under Camelot Castle -- and she's very bad news for the kingdom." Maureen's other credits can be seen on
her IMDb page.
Lindsay Duncan's Queen Annis is also a villain who wants to conquer Camelot with her army.
Gemma Jones' "The Cailleach" is described as a "terrifying gatekeeper" (see her photo
at this link) and will appear in the first episode when Morgana tears "the mystical veil between our world and the next."