The character, who was played by Asa Butterfield in the first two series of Merlin, is due to return in Series 5 played by Alexander Vlahos. Speaking to Digital Spy recently at San Diego’s Comic-Con, Colin Morgan (Merlin) described the character as the “biggest threat there’s ever been. Anyone who knows the legend knows what Mordred is destined to do.”

“We tip a wink to the Arthurian legend of Mordred,” acknowledged executive producer Johnny Capps, “but in our classic way with the series we’ve brought lots of twists and unexpected turns. What happens with Mordred is quite unexpected, and I think the audience will enjoy the way we’ve played round with the expectations of his character.”

On the series, the Great Dragon has already hinted that Mordred will bring about Arthur’s death – and form an alliance with Morgana.

“You can’t tell the story of Morgana without Mordred,” said Katie McGrath (Morgana). “They are interlinked, they are entwined, and from the very first episode, you see that. You see that the bond they have is unbreakable. [He]’s almost the reason that she accepted her magic.”

The cast also revealed more about their characters’ directions in Series 5. “Merlin is becoming more ruthless,” Morgan said, “because he is becoming more solid in his beliefs, and seeing things in a new way, right from the beginning. He sees something in particular that puts him on absolute drive, that puts him on a ruthless mode, I guess. I think he fears that side of himself, in a way. When he killed Agravaine, he wanted to do it, but he didn’t want to do it, but he had to do it… that’s Merlin’s dilemma: his power is also his curse.”

“[Gwen]’s a lot more assertive,” revealed Angel Coulby (Guinevere), “having in the past been a little bit unsure of herself, and never quite believing her worth, she now has accepted that she’s good for the job, basically. She’s fulfilling the role very well.”

Coulby added: “She’s a good queen, which I always thought she would be. She’s very fair and just, and very caring still, but has much more of a sense of duty.”

What are you most looking forward to about Mordred’s return? Let us know below…

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