Originally the producers wanted to bring the character Gilli back but the actor Harry Melling had other commitments during the filming process. This led to a new character being introduced, that being Daegal portrayed by Alfie Stewart. Several lines/sequences shown during the episode that this was indeed set up for Gilli's character.
Alfie Stewart's (Daegel) co-star Georgina Campbell in the TV series 'Sadie J' has worked with Katie McGrath (Morgana) in the movie 'King Arthur: Legend of the Sword'. They played Kay and Elsa respectively.