I could see it going a few ways, either two (or more?) cards, for kid Aang and for Avatar powers unlocked Aang (Considering the LotR set had several versions of some folks, it does make sense.), some sort of Saga type thing, or a DFC in some way. If he did have a casting cost for Avatar Aang, I think 5 color would get chosen over the more thematically appropriate four… though I’m very good at being proven wrong.