Board Thread:What If?/@comment-5674726-20130816211001/@comment-5674726-20130819001417

If the writers/showrunners had delivered an explanation for her sudden change, maybe an enchantment/spell by Morgause, for example, she would have betrayed Merlin anyway.

I'd say that by Season Four, certainly by Season Five, they may have felt that they'd taken Morgana to too much of an extreme as a villain to reveal that she had been enchanted. I can't see them wanting to risk that Merlin would be blamed for not giving her the benefit of the doubt when she first returned after being kidnapped by Morgause, with an implausible story - I'll give Uther a pass because he was too desperate to get his daughter back to look a gift horse in the mouth but Merlin and Gaius should have been more suspicious - and a personality shift, as thousands of lives could have been saved if he had realised that she was enchanted sooner.