In case text is too small to see, you can click on the pic to open a bigger version. But if it's still too small, here's what's being said:
Zuko: Teach me how to do that! ("that" = the barrier thingy Gy did)
Gyendal: I don't think so, kid, your magic works differently from mine

Yeeeeah.... I don't think ANY of the bending in Avatar can be used to make a barrier like that. Try asking Agas, Zuzu, he might know a bit more... And it's okay for Gy to call Zuzu "kid" because Gy is at least 10 years older as human. 800+ if you count the "frozen" years of Gy being a vampire.

No, I didn't suddenly become an Avatar fan I can draw casual fanarts for no reason, so there!

Well, okay, this is sooooort of a follow up of the previous crossover. Googling proper screenshots is hard, I always end up finding a massload of fanart. One of the first few official stuff that I landed was Zuko as firelord in the sequel comic The Promise. That firelord outfit is spiffy and totally for the win, so I wanted to draw it. Then I wondered how similar Gy and Zuzu's outfits are, so I drew them together. Which... somehow ended up being a sparring moment. Sort of.

Oh yeah, and because I like dorky emo characters. Ponytail!Zuzu is full of narm. Funny, but the eye-rolling kind. Emo!Zuzu is adorkably cute just like pet!Gyendal *cough cough*

And that kick Zuko did is not actually a firebending move. Not that I know of anyway. Firebending moves are based off Northern Shaolin kungfu, and that kick that I drew is NOT from Northern Shaolin. Then again, many martial arts look the same in still poses, so what do I know? It's usually the transition between moves that makes martial art styles different.

I'm loving how much I've improved in terms of figure drawing. Few months ago it woulda took me an hour just to draw the kick.