Ayelet Zurer as Viviane
Odeya Rush, Rachel Weisz as Morgaine
Kate Mara as Igraine
Michael Marcus, James Purefoy as King Lot
Jenna Thiam, Franziska Petri as Morgause
Billy Howle as Gawaine, Joe Cole as Agravain, George MacKay as Gareth, Lucas Hedges as Gaheris
Ezra Miller as Mordred | Gwydion
Oscar Isaac as Lancelet | Ban of Benwick