Perspective. How do you define right and wrong?

While listening to Goyte's newest song, Somebody that I Used to Know, I had a writer's revelation about perspective and how it plays into the depth of an antagonist. Goyte starts the song by singing about how cruel his love went about their breakup. But then you get the woman, sung by Kimbra, who tells how cruel he was during their relationship and how she had to break up the way she did.

This is interesting, and a great writing method that not many writers utilize to its full potential (including myself). Done right, this can be very rewarding to the reader.

One good sign of a well thought-out antagonist for me is his/her believability in their perspective of right or wrong. Their sense of purpose is justified to them. I think the best writing is when the author can make the reader empathize with the antagonist and even have the reader wonder about his or her own position. Even more important, maybe even question the position of the protagonist(s).

My favorite antagonist of all time is The Deceiver from the Chronicles of the Shadow War (a series continuation of the Willow story). That character really defines the duality of choice for everyone and how easy it is to become the antagonist while seeing yourself as the protagonist.

Literally.

Throughout the stories, The Deceiver is attempting to take over Princess Elora's body, to rule over the 12 Realms. The band of Elora's friends, including the mage Willow (known from the second book on as Thorn), tries to save Elora and the world as they know it. Maybe even bring peace to the 12 Realms if all works out.

You find out in the end that The Deceiver is actually Princess Elora from the future. She goes back in time fix her own mistakes by attempting to "take over" herself as a toddler and start over. This slices time and creates a parallel existence. It's not until the end when The Deceiver confronts herself, Elora, that you see she really thinks she is the protagonist trying to save the world.

In the scene of them mind walking through a museum, the two woman use a Monet-style painting (the ones where all the little dots make up a scene) to see each other's perspective. The Deceiver points to each dot, which represents a moment in her life, and explains the reasons behind each action. She is trying to get Elora to understand the importance of her (er- their) mission. Elora pulls The Deceiver back to see the picture as a whole and shows what she's done to the world by her lifetime of small actions.

It is truly a revelation to The Deceiver that she is in fact the antagonist.

So, who is your favorite antagonist and why? What makes them stand out from the other villains?