Board Thread:General Discussion/@comment-24762954-20140406143644/@comment-5102537-20140408123557

He carried indeed a heavy weight on his shoulders. It would be totally normal and forgivable for Merlin to lose his way and changing, if he hadn't been described as the hero who was morally right.

I don't know if it all was enough to get insane, but it surely was enough to make him act differently - which he did indeed from season four onward, only in a quite weird way that was always justified. A normal person most certainly would have suffered from depression and/or gotten furious at some point.

Unfortunately, the show missed to deal with a propper development of the characters, Merlin included. His desperation and anger due to the huge responsibility he had would have made a great contribution to a conflicted character.