While far from my favorite incarnation of the character Merlin in all fiction, he was a decent character on Once Upon a Time.
I thought it was clever that he was the movie usher who warns Emma as a kid, this is before we all know he is Merlin.
But his magic was a bit disappointing, he ends up a pawn too easily.
We learn that his love Nimue became the original Dark One, and her evil spirit has remained in the dagger and was up to much trouble.
And he dies starting off a new curse, a bit lame for his ending.