<Li> Richard Wilson as Gaius </Li> <Ul> <Li> John Hurt as the Great Dragon (voice) </Li> <Li> Rupert Young as Sir Leon </Li> <Li> Eoin Macken as Sir Gwaine </Li> <Li> Adetomiwa Edun as Sir Elyan </Li> <Li> Tom Hopper as Sir Percival </Li> <Li> Alexander Vlahos as Mordred </Li> </Ul> <Li> John Hurt as the Great Dragon (voice) </Li> <Li> Rupert Young as Sir Leon </Li>

When does arthur find out about merlins magic