Still, it would have been nice to have seen where this underground sprang up from.
So, who should the Season Two Big Bad be?
I say make it an evil earth bender. I've always felt that earth bending is the most powerful set to have. I think my favorite battle from the old series is in "The Earth King" when Team Avatar has to fight their way through hundreds of earth bending guards to get to the king. That was epic stuff. As long you're on the dirt ground, I would think a good earth bender would be nigh unstoppable.
Not to mention we always had evil fire benders in the old show and we just had an evil water bender. And only Tenzin or his little kids aren't going evil