Merlin’s S5 character development was natural and reasonable in face of the circumstances that surrounded him. The idea of a darker Merlin who slowly becomes more isolated and crumbles under the weight of destiny is awesome and sad at the same time. His character development is great, actually. And well written.
Merlin was exhausted from years of living a double life, burnt out on hope of ever realizing his dream of living freely with his magic in the future, and terrified of possibly being at least partially responsible for Arthur’s impending death. He brooded more and smiled less.
Yet, he still took the time to help Daegal - a complete stranger - when the boy convinced him that his sister needed his help (while knowing evil Gwen is an active threat). He still shared his food with him, and offered him friendship and kindness, with no thought of reward for himself. He still mourned him when he died, even though the boy’s earlier betrayal had led to grievous injury to Merlin himself.
So, yes, Merlin became darker, but that seemed more due to desperation and depression than anything else.
And that’s why i love this scene so much
We’re reminded of how pure of heart he really is, how much joy he draws from the simple beauty of magic. This is the most beautiful moment of the show ❤