User blog comment:Morganaforever/Episode Review: The Diamond of the Day Part 1/@comment-5253758-20121222205654/@comment-109.153.188.118-20121222211402

He will stay old. It just fits:

All of the Part 2 previews we've seen show Merlin in his old form only.

In the legend he is much older than Arthur.

It's his 'true form', according to Balinor.

The Merlin who said 'I am a sorcerer, I have magic' sounded a bit older than young Merlin, though not quite the whole hog.