Merlin first noticed it at the funeral for Gaius.

How he hadn't changed.

He dismissed the thought, originally, but years later Gwen mentioned how young he looked despite the time that passed.

It was then that Merlin took a look around him, at his friends, at himself.

Still no change.

At this point he was worried, and made a decision to seek out Kiligarrah.

He was not sure what to expect from the dragon.

Maybe amusement?

Over the ridculous idea that a mortal didn't age.

However, it was not as expected.

The dragon simply looked at him with knowing eyes and said, "Young warlock, you are magic given form. You are Emrys. Old age was never to be your downfall, you will survive through the ages."

Merlin didn't know what to do after that.

He knew he'd have to leave Camelot before people noticed.

But when?

Where would he go?

Questions ravaged his head and Kiligarrah gave him no answers.

So here he was. No longer under the guise of an old man but, himself siting on a barstool drinking something that was probaly going to get him drunk.

Gwaine was wrong about many things, but not him being a lightweight.

He turned around at the commotion that had started and his heart stopped.

It was Arthur, bullying some waiter that suspiciously looked like the servent helped all those years ago.

More out of pity than an actual want to defend the poor man he got up and picked up the tray that he dropped in fear and handed it to his owner before turning to Arthur and saying the exact thing he said the first time,

"Hey that's enough."