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 Anna Skellern as Arwen Sam O'Mahony as Warin Lily Walsh as Young Guinevere Lorcan Melia as Mary's son Melanie Clark-Pullen as Mary Nick Devlin as Herlewin Oscar Quinn as Young Kay Rachel Joyce as Sara Shay Macleod as Young Arthur