[the smiling weirwood]

A Flight of Dragons was one of my favorite movies as a child!

But in answer to your question...

I know it wasn't a personified enemy, but the corruption of the male side of magic in The Wheel of Time was a very real and powerful enemy and yet they defeated it just by running it through a filter. It was kind of anti-climatic for such a huge event considering it was a fundamental change to their world and hardly anyone took note of it. One of the reasons I stopped reading WoT, apart from the lack of plot progression and deeper characterization after the third book.