User blog comment:Ellyby/Series final - fulfilling both destinies/@comment-37001937-20181017190717

I suppose the caveat we all missed, or the Dragon forgot to warn about was that Arthur would die. "If the boy lives, you won't fulfill your destiny." Merlin's inaction towards Morgana also contributed to the early death of the Once and Future King. I don't know anymore. The writers wanted to have it both ways-do the legends, and do their own interpretation, and by doing so killed Arthur before he became legendary. The golden age of Albion was never shown. Merlin wasn't even present at Gwen's coronation. He did feel that he had failed, and perhaps that's why he didn't go back to Camelot after Arthur's death.