User blog comment:M Bierhoff/Emrys/@comment-4126310-20111018044844

It's his True Name; they tend to be important. It's also a Celtic name, which in the series signifies a connection to magic and magical creatures, along with Old English. Merlin is a young man with atypically strong magic powers who has to hide them from his countrymen; it's fitting that he should have both an unassuming normal name and a more mystical one.