User blog comment:Edrea/Is Morgana more powerful than Merlin?/@comment-5102537-20130628131605

It's a miracle why Morgana suddenly became immune to mortal weapons and could only be killed by powerful magic. It also makes a mockery of her injury in "The Crystal Cave" when she fell down the stairs due to Merlin's magic. Merlin used magic that caused her fall but it was a common injury that threatened her life and would have killed her after all.

She must have become resistent to mortal weapons somewhere during season four or five, maybe after Aithusa healed her in the season four finale. Before that she was severly injured by the fight. So my guess is that she was made "immortal" in season five, only without any explanation and due to plot convenience so that she could only be killed by Merlin wielding Excalibur.

Her growing powers often seemed to be greater than Merlin's powers. And again I think it was done to simply deliver an enemy that was a believable threat to Merlin, yet it wasn't worked out properly and/or believable. She was a High Priestess of the Triple Goddess, so maybe she gave Morgana the great powers she needed. However, if so, they should have mentioned it somewhere in order to explain the reason to us. The way it ws done, Morgana suddenly became a powerful witch who seemed to be more powerful than even Merlin, yet nobody knows why or how.