KingD19
Shai-Gen's Enigmatic Wong
He's also the only Avatar Antagonist to actually truly lose something. Amon died, but he died happy with his brother. Unalaq didn't lost anything. He didn't even seem to really care for his children before he kicked the bucket.
Zaheer not only got 99% of the way to hitting his end game, in the process he lost two very good friends and the love of his life because of what he brought about. He learned to fly, and now he's shackled in an underground cave. Zaheer's got onion layers.
Also his name is pretty cool.