What are your "favorite" villain twists to write about in a Fantasy setting?

My personal favorite, along with my siblings is definitely the hero was the villain all along...

They just didn't know they were.

It's seriously a awesome idea to me and I hope to include this idea in one of my universes soon.

What is your favorite villain twists to write in a Fantasy setting? Underrated tropes and villain types?

Please share your thoughts and examples!

Thank you 😊.