Katherine Langford as Nimue
Devon Terrell as Arthur
Gustaf Skarsgård as Merlin
Shalom Brune-Franklin as Morgana
Billy Jenkins as Squirrel
Lily Newmark as Pym
Daniel Sharman as Weeping Monk
Peter Mullan as Father Carden
Matt Stokoe as Gawain / Gauvain
Sebastian Armesto as King Uther
Emily Coates as Iris
Jasper Jacob as Sir Borley
Adaku Ononogbo as Kaze
Clive Russell as Wroth the Tusk Commander
Ashley Bannerman as Cora (Faun Woman)
Polly Walker as Lady Lunete
Sofia Oxenham as Eydis
Jóhannes Haukur Jóhannesson as Cumber the Ice King
Sophie Harkness as Sister Celia
Nikolaj Dencker Schmidt as Dof
Zoe Waites as The Widow
Catherine Walker as Lenore
Peter Guinness as Sir Ector
Bella Dayne as Red Spear