User blog comment:General MGD 109/Who's most powerful?/@comment-4636304-20111204222450

Interesting. I assumed that Nimueh was probably the most powerful of her time,  I did notice though her eyes never glowed gold like the others. However Merlin did defeat her rather easily,

Morgause-I often wondered about her. If she was trained by the High Priestesses of the Old Religion, could Nimueh been one of her teachers. She was undoubledly a force to be reckoned with.

Morganna-She had a total of two separate years to learn how to use her powers by Morgause. Given her legendary powers she was said to possess, I say she by far surpassed Morgause in power and according to Gaius, is highly skilled. But then, she did have someone to teach her, Merlin has more or less self taught himself. And with no restraints or reason for secrecy, she can practice a lot more openly than Merlin.

Mordred-Powerful at his young age, can't help but wonder just how powerful as an adult he will be. I hope he returns in series 5. He is the one person who can tell Morganna about Emrys.

Merlin-The most powerful wizard to ever exist. And probably the only one more powerful than Morganna. Id say they are probaby on about equal terms now, But as he gets older, his powers will by far surpass even hers.

Gaius-Id like to learn more about Gaius and his relationship with Nimeuh. Though he has not used magic in many years, he still can take care of himself. I wonder how powerful and skilled he was in his younger days.