This was most likely somewhere between 2005 and 2010, and I saw it on a local TV station that licensed it (as the channel was in my native language but the show was in English). I realise the title is a bit vague, but that's because I only really remember three scenes:
Atop a cliff the main character is confronted by an assassin aiming to kill him. I'm sure there was a wast amount of smoke, that the character has to break through, before he jumps into the water (I think). I'm sure that the events were preceded by the local village burning during the day (possibly by the assassin).
The main character (a young man with shoulder length blonde hair) is sailing through a water filled canyon (visually similar to this scene from Vinland Saga) on a small boat. I remember that this was the end of the episode with a voice-over by (I think?) an old man.
This last scene may have happened just before the second scene - a giant door somewhere underground was shaking and was then broken apart from the inside. I think that there were mages/wizards trying to stop this but they couldn't.
I think that the main character was (a soon to be) mage, but being originally from a village (the one that burns in 1.). And yeah, I know all this sound as generic as a show can be, but I genuinely cannot remember anything more specific.
I'm pretty sure that all these scenes happened in the same episode (or at least in sequential episodes). I know it's not Merlin and I'm pretty sure it's not The Legend of the Seeker.