My mind was just blown, even if I did have some inkling that this was going to come out at some point. Family ties are the strongest, even if people don't want to admit that fact about blood bonds. And those ties are also the hardest to keep secret. I've loved this whole saga of Amon - and love it even more now that his hypocrisy is confirmed. It seems like that's human nature, hypocrisy. The beginning battle as the fleet arrived felt very WWII, and like Hilter was not the blonde-haired, blue-eyed Aryan he promoted, Amon is not the non-bender he promotes. It's beautiful to watch unfold.
Beyond that, I'm very excited by the prospect of meeting another of Aang's children, especially if this one received the name Boomy. Can't wait. And dammit, Mako, don't go trying to kiss Korra again. It's not the time nor place. You'll only dig yourself deeper, boy, and she'd reject you at this point anyhow.