Guest Stars Sean Pertwee as Ector Janine Wood as Bela Co Starring Diarmaid Murtagh as Brastias Jamie Downey as Ulfius Lara Jean Chorostecki as Bridget George McMahon as Messenger Daragh O'Malley as Leodegrance Melanie Clark-Pullen as Mary Anna Skellern as Arwen Lily Walsh as Young Guinevere Lorcan Melia as Mary's son Nick Devlin as Herlewin Oscar Quinn as Young Kay Rachel Joyce as Sara Sam O'Mahony as Warin Shay Macleod as Young Arthur